Add trust features: history, trash, export, and collection sharing

Implement Notion-like upgrade phase 4: append-only page revisions with restore-as-a-new-version; recoverable bookmark/page/collection deletions whose restores never resurrect public flags or shares; owner-scoped JSON export; and explicit, revocable read-only collection sharing with owner-only mutations and no transitive third-party bookmark leaks. Add migration 009, API/docs, integration coverage, and page/collections/trash UI.

API.md

@@ -116,8 +116,11 @@ test-only). CardDAV keeps the configured HTTPS port.
 | PUT | `/api/pages` | `{ok:true}`; complete `{order:[id,...]}` |
 | GET | `/api/pages/{id}` | Page plus ordered `bookmarks:[{bookmark}]`, owner-scoped `backlinks:[{id,title,updatedAt}]`, resolved outgoing `links:[{id,title}]`, and `embeds:[{collectionId,viewId,position,collection,view}]` |
 | PATCH | `/api/pages/{id}` | Updated page; `{title?,content?,pinned?,icon?,parentId?,version?,addBookmarkId?,removeBookmarkId?}`. `version` (the base revision from GET) is REQUIRED with `content`: 400 when missing, 409 when stale. Metadata-only patches (including moving a page) stay version-free and do not bump the revision. Moving under itself or a descendant is rejected 400 (no cycles) |
-| DELETE | `/api/pages/{id}` | `{ok:true}`; keeps bookmarks and promotes child pages to the top level |
 | GET | `/api/pages/{id}/backlinks` | Owner-scoped `[{id,title,updatedAt}]` from `PageLink` — the pages whose Markdown links here |
+| GET | `/api/pages/{id}/revisions` | Version history metadata `[{id,version,title,icon,createdAt,length}]`, newest first; bodies fetched separately |
+| GET | `/api/pages/{id}/revisions/{revisionId}` | Full immutable revision snapshot `{...,content}` |
+| POST | `/api/pages/{id}/revisions/{revisionId}/restore` | Restores a snapshot as a **new** version; body `{version}` (current base) — 400 missing, 409 stale. The restore itself is recorded in history |
+| DELETE | `/api/pages/{id}` | Moves the page to Trash; keeps bookmarks and promotes child pages. Restoring also restores its revisions and creates a new revision |
 | GET | `/api/pages/{id}/markdown` | Markdown attachment |
 
 ### Connected pages (phase 3)
@@ -139,15 +142,39 @@ in the same transaction as every content save:
   its bookmarks. Deleting a collection removes its embeds; deleting a view
   falls the embed back to the collection's default view.
 
+### Trust (phase 4)
+
+Deleting a bookmark, page or collection now moves it to the owner's Trash.
+The snapshot is taken in the same transaction as the hard delete and includes
+intrinsic content plus owner-scoped links (tags, page links, collection
+memberships, page revisions). It deliberately excludes access grants:
+bookmark public flags, bookmark/tag shares and collection shares are never
+restored, so revoking access while an item is in the Trash cannot be undone by
+restoring it. Deleted bookmarks keep their existing delete endpoints; the UI
+and docs now call this “move to trash”.
+
+| Method | Path | Returns / behavior |
+|---|---|---|
+| GET | `/api/trash` | Owner's deleted items `[{id,type,originalId,title,deletedAt}]`, newest first |
+| POST | `/api/trash/{id}/restore` | Restores the item; 404 for another owner. Page restores recreate their history and append a new revision. Neither bookmark `isPublic` nor any share is restored |
+| DELETE | `/api/trash/{id}` | Permanently removes one Trash entry (explicit purge) |
+| GET | `/api/export` | Owner-scoped structured JSON archive: user, bookmarks, tags, pages (content + revisions), collections (properties, views, items, shares) and contacts. Credentials are never exported |
+
 ## Collections
 
 Contextual workflows over existing bookmarks (phase 2 of the Notion-like
-upgrades). Collections are owner-scoped; membership references bookmarks
-without owning them — removing an item or a whole collection never touches
-the bookmark. Membership never broadens access: items whose bookmark the
-caller cannot see are omitted from lists/counts and behave as not-found for
-mutations; re-sharing restores the membership. Every mutating PATCH requires
-the expected `version` (400 missing, 409 stale). Indirect mutations advance
+upgrades). Collections are owner-scoped unless explicitly shared; membership
+references bookmarks without owning them — removing an item or a whole
+collection never touches the bookmark. An explicit `CollectionShare` gives a
+recipient read-only access to the collection and the **narrowed** bookmark
+projection for member bookmarks **owned by the collection owner**. A bookmark
+that the collection owner can only see through someone else's share is
+omitted, so collection sharing never passes a third-party grant onwards.
+Revoking the share or removing the item removes that access immediately, and
+mutations remain owner-only. Items whose
+bookmark the caller cannot see are omitted from lists/counts and behave as
+not-found for mutations; re-sharing restores the membership. Every mutating
+PATCH requires the expected `version` (400 missing, 409 stale). Indirect mutations advance
 revisions too (review CR-09): item reorder bumps every affected item's
 version, and property deletion bumps the versions of items whose value it
 dropped and views whose filter/sort definition it changed. Deletions are
@@ -156,11 +183,13 @@ from a client snapshot.
 
 | Method | Path | Returns / behavior |
 |---|---|---|
-| GET | `/api/collections` | Owned collections with `_count.{items,properties,views}`; item counts include only bookmarks the caller can see |
+| GET | `/api/collections` | Owned **and explicitly shared** collections with `shared`, `owner`, `_count.{items,properties,views}`; item counts include only bookmarks the caller can see |
 | POST | `/api/collections` | 201 detail `{...collection,properties:[],views:[default Table view]}`; body `{name,description?,icon?}` |
-| GET | `/api/collections/{id}` | Collection plus ordered `properties`, `views` and authorized `_count.{items,properties,views}` |
-| PATCH | `/api/collections/{id}` | Updated collection; `{version,name?,description?,icon?}`, bumps `version` |
-| DELETE | `/api/collections/{id}` | `{ok:true}`; memberships/properties/views cascade, bookmarks kept |
+| GET | `/api/collections/{id}` | Readable collection detail (owner or share recipient) plus ordered `properties`, `views`, authorized `_count`, `shared`; owner also gets `sharedWith` |
+| PATCH | `/api/collections/{id}` | Updated collection; `{version,name?,description?,icon?}`, bumps `version`; owner only |
+| DELETE | `/api/collections/{id}` | Moves the collection to Trash; memberships/properties/views cascade, bookmarks kept; owner only |
+| POST | `/api/collections/{id}/share` | Owner only; `{userIds:[...]}` grants read-only access, idempotent |
+| DELETE | `/api/collections/{id}/share/{userId}` | Owner only; revokes read-only access immediately |
 | POST | `/api/collections/{id}/properties` | 201 property; `{name,type,config?}`. Types: `TEXT,NUMBER,SELECT,MULTI_SELECT,DATE,CHECKBOX,URL` (`RELATION` reserved, rejected). SELECT config `{options:[{label,color?}]}` — the server assigns stable option ids; DATE config `{mode:"date"\|"datetime"}`. Duplicate name → 409 |
 | PATCH | `/api/collections/{id}/properties/{propertyId}` | Updated property; `{version,name?,position?,config?}`. Type and date-mode changes are rejected (400) — conversion must never destroy values. Option updates send the full list: existing ids rename/recolor (identity preserved), omitted ids are removed but refused (400 with the using-item count) while any item still carries them |
 | DELETE | `/api/collections/{id}/properties/{propertyId}` | `{ok:true}`; strips the property's values from all items and its clauses/sorts/grouping from saved views |

PLAN.md

@@ -80,9 +80,6 @@ keeping its own passwords.*
 
 **Product features**
 
-- Collections can't be shared — they're private to their owner.
-- No page history (can't see or restore older versions).
-- No trash — deletes are permanent.
 - Calendar and list views for collections are stored but still display as
   tables.
 - Alerts only show inside the app — nothing is emailed or pushed to you.
@@ -168,15 +165,18 @@ maintenance rather than a separate milestone.
 
 ### 3–6 months: grow the product
 
-- **Page history and trash** — see old versions, restore them; deleted
-  things are recoverable.
+- **Page history and trash** — done: versioned history with restore, and
+  recoverable bookmark/page/collection deletes. Restores never resurrect a
+  revoked share or public link.
 - **Nested pages and backlinks** — done: a real page tree, "what links here"
   that never shows titles you're not allowed to see, and live collection
   views embedded in pages.
-- **Collection sharing** — the big one. Explicit, shown in the UI, and
-  revocable. Design the permission rules first (a project must never
-  accidentally widen who can see a bookmark), then build it. Once it
-  exists, cross-project "relation" columns can follow.
+- **Collection sharing** — done: explicit, disclosed, revocable read-only
+  shares; recipients see the narrowed bookmark view, and removing an item or
+  revoking access removes it immediately. Cross-project "relation" columns
+  can follow.
+- **Structured export** — done: an owner-scoped JSON archive richer than the
+  per-item Markdown downloads.
 - **Alerts that reach you** — email or webhook when a due date hits or an
   email watcher matches. Turns the app from a dashboard into a notifier.
 - **RSS watchers** — "tell me when this feed mentions X." Reuses everything

db/migrations/009_trust.sql

@@ -0,0 +1,48 @@
+-- 009_trust.sql — Notion-like upgrades phase 4 (trust).
+--
+-- Server-side page revision history, recoverable deletions, and explicit
+-- collection sharing.
+--
+-- Trust rules:
+--   * Every committed page content version is snapshotted. Restoring a
+--     revision writes a NEW version (history is append-only) and the restore
+--     itself is recorded.
+--   * Trash is a per-owner snapshot taken in the same transaction as the
+--     delete. It restores intrinsic data and owner-scoped relationships, but
+--     never access grants (bookmark public flags, bookmark/tag shares,
+--     collection shares). A granted access revoked while an item was in the
+--     trash cannot come back with the item.
+--   * Collection sharing is read-only and revocable. Recipients see member
+--     bookmarks through the narrowed shared projection; mutations stay
+--     owner-only. BookmarkVisible gains the explicit collection-share edge.
+
+CREATE TABLE IF NOT EXISTS "PageRevision" (
+  id text PRIMARY KEY,
+  "pageId" text NOT NULL REFERENCES "Page"(id) ON DELETE CASCADE,
+  version integer NOT NULL,
+  title text NOT NULL,
+  content text NOT NULL,
+  icon text,
+  "createdAt" timestamptz NOT NULL DEFAULT now(),
+  UNIQUE ("pageId", version)
+);
+CREATE INDEX IF NOT EXISTS "PageRevision_pageId_version_idx" ON "PageRevision"("pageId", version DESC);
+
+CREATE TABLE IF NOT EXISTS "Trash" (
+  id text PRIMARY KEY,
+  "ownerId" text NOT NULL REFERENCES "User"(id) ON DELETE CASCADE,
+  type text NOT NULL CHECK (type IN ('bookmark','page','collection')),
+  "originalId" text NOT NULL,
+  data jsonb NOT NULL,
+  "deletedAt" timestamptz NOT NULL DEFAULT now(),
+  UNIQUE (type, "originalId")
+);
+CREATE INDEX IF NOT EXISTS "Trash_ownerId_deletedAt_idx" ON "Trash"("ownerId", "deletedAt" DESC);
+
+CREATE TABLE IF NOT EXISTS "CollectionShare" (
+  "collectionId" text NOT NULL REFERENCES "Collection"(id) ON DELETE CASCADE,
+  "userId" text NOT NULL REFERENCES "User"(id) ON DELETE CASCADE,
+  "createdAt" timestamptz NOT NULL DEFAULT now(),
+  PRIMARY KEY ("collectionId", "userId")
+);
+CREATE INDEX IF NOT EXISTS "CollectionShare_userId_idx" ON "CollectionShare"("userId");

db/schema.sql

@@ -236,6 +236,22 @@ CREATE TABLE "PageLink" (
 );
 CREATE INDEX "PageLink_targetPageId_idx" ON "PageLink"("targetPageId");
 
+-- 2.13c PageRevision: server-side content history. A snapshot is recorded for
+-- every committed content version (including restore, which is a new version)
+-- so an old draft can be inspected and restored without ever rewriting the
+-- past. Revision rows cascade with their page.
+CREATE TABLE "PageRevision" (
+  id text PRIMARY KEY,
+  "pageId" text NOT NULL REFERENCES "Page"(id) ON DELETE CASCADE,
+  version integer NOT NULL,
+  title text NOT NULL,
+  content text NOT NULL,
+  icon text,
+  "createdAt" timestamptz NOT NULL DEFAULT now(),
+  UNIQUE ("pageId", version)
+);
+CREATE INDEX "PageRevision_pageId_version_idx" ON "PageRevision"("pageId", version DESC);
+
 -- 2.14 SignalSource
 CREATE TABLE "SignalSource" (
   id text PRIMARY KEY,
@@ -294,6 +310,22 @@ CREATE TABLE "AppSetting" (
   "updatedAt" timestamptz NOT NULL DEFAULT now()
 );
 
+-- 2.16b Trash: recoverable deletions (trust phase). The row is a private
+-- per-owner snapshot taken in the same transaction as the hard delete. It
+-- keeps intrinsic data and owner-scoped relationships, but deliberately not
+-- access grants (bookmark shares, public flags, collection shares): restoring
+-- an item never resurrects a grant that was revoked while it sat in the bin.
+CREATE TABLE "Trash" (
+  id text PRIMARY KEY,
+  "ownerId" text NOT NULL REFERENCES "User"(id) ON DELETE CASCADE,
+  type text NOT NULL CHECK (type IN ('bookmark','page','collection')),
+  "originalId" text NOT NULL,
+  data jsonb NOT NULL,
+  "deletedAt" timestamptz NOT NULL DEFAULT now(),
+  UNIQUE (type, "originalId")
+);
+CREATE INDEX "Trash_ownerId_deletedAt_idx" ON "Trash"("ownerId", "deletedAt" DESC);
+
 -- 2.16 SharedDate
 CREATE TABLE "SharedDate" (
   id text PRIMARY KEY,
@@ -325,6 +357,19 @@ CREATE TABLE "Collection" (
 );
 CREATE INDEX "Collection_ownerId_idx" ON "Collection"("ownerId");
 
+-- 2.17b CollectionShare: explicit, revocable read access to a collection.
+-- Recipients get the narrowed bookmark projection for member bookmarks (via
+-- BookmarkVisible); sharing therefore widens access only by the owner's
+-- deliberate action, is disclosed in the share UI, and revocation removes
+-- access immediately. Mutations remain owner-only.
+CREATE TABLE "CollectionShare" (
+  "collectionId" text NOT NULL REFERENCES "Collection"(id) ON DELETE CASCADE,
+  "userId" text NOT NULL REFERENCES "User"(id) ON DELETE CASCADE,
+  "createdAt" timestamptz NOT NULL DEFAULT now(),
+  PRIMARY KEY ("collectionId", "userId")
+);
+CREATE INDEX "CollectionShare_userId_idx" ON "CollectionShare"("userId");
+
 CREATE TABLE "CollectionProperty" (
   id text PRIMARY KEY,
   "collectionId" text NOT NULL REFERENCES "Collection"(id) ON DELETE CASCADE,

internal/db/bookmarks.go

@@ -41,4 +41,11 @@ const BookmarkViewerView = `CASE WHEN b."ownerId"=$2 THEN ` + BookmarkOwnerView
 // it, including bookmarks other recipients added. The share UI says so.
 const BookmarkVisible = `(b."ownerId"=$2 OR EXISTS(SELECT 1 FROM "BookmarkShare" s WHERE s."bookmarkId"=b.id AND s."userId"=$2)
  OR EXISTS(SELECT 1 FROM "BookmarkTag" bt JOIN "TagShare" ts ON ts."tagId"=bt."tagId" WHERE bt."bookmarkId"=b.id AND ts."userId"=$2)
+ -- Explicit collection sharing (trust phase): membership in a collection the
+ -- bookmark's OWNER deliberately shared grants the narrowed bookmark
+ -- projection. The owner match is essential: a collection can contain
+ -- bookmarks merely shared with its owner, and sharing that collection must
+ -- not widen a third party's grant. Removing the item or revoking the share
+ -- removes this edge immediately.
+ OR EXISTS(SELECT 1 FROM "CollectionItem" ci JOIN "Collection" c ON c.id=ci."collectionId" JOIN "CollectionShare" cs ON cs."collectionId"=ci."collectionId" WHERE ci."bookmarkId"=b.id AND cs."userId"=$2 AND c."ownerId"=b."ownerId")
  OR EXISTS(SELECT 1 FROM "SharedDate" sd WHERE sd."creatorId"=b."ownerId" AND sd."recipientId"=$2 AND (b."dueDate" AT TIME ZONE 'UTC')::date=sd.date))`

internal/handlers/bookmarks.go

@@ -363,7 +363,15 @@ func HandleBookmarksUpdate(w http.ResponseWriter, r *http.Request) {
 	respond(w, 200, v, e)
 }
 func HandleBookmarksDelete(w http.ResponseWriter, r *http.Request) {
-	e := remove(r, "Bookmark", r.PathValue("id"), "ownerId")
+	// Recoverable delete (trust phase): snapshot intrinsic fields and
+	// owner-scoped links in the same transaction as the hard delete. Shares
+	// and the public flag are deliberately not restored.
+	e := db.Transaction(r.Context(), database(r), func(tx *sql.Tx) error {
+		if e := lockUser(r, tx); e != nil {
+			return e
+		}
+		return trashBookmark(r, tx, r.PathValue("id"))
+	})
 	respond(w, 200, OK{true}, e)
 }
 

internal/handlers/collections.go

@@ -63,6 +63,15 @@ var (
 func collectionOwned(r *http.Request, q db.Queryer, id string) (object, error) {
 	return db.One(r.Context(), q, `SELECT to_jsonb(c) FROM "Collection" c WHERE c.id=$1 AND c."ownerId"=$2`, id, user(r))
 }
+
+// collectionReadable admits the owner and explicit recipients of a
+// CollectionShare. Mutating surfaces keep using collectionOwned, so a shared
+// reader can never rename, delete, reorder, or edit collection content.
+func collectionReadable(r *http.Request, q db.Queryer, id string) (object, error) {
+	return db.One(r.Context(), q, `SELECT to_jsonb(c)||jsonb_build_object('shared',c."ownerId"<>$2)
+		FROM "Collection" c WHERE c.id=$1 AND (c."ownerId"=$2 OR EXISTS(
+			SELECT 1 FROM "CollectionShare" s WHERE s."collectionId"=c.id AND s."userId"=$2))`, id, user(r))
+}
 func collectionProperties(r *http.Request, q db.Queryer, collectionID string) ([]object, error) {
 	return db.Many(r.Context(), q, `SELECT to_jsonb(p) FROM "CollectionProperty" p WHERE p."collectionId"=$1 ORDER BY p.position,p.id`, collectionID)
 }
@@ -99,6 +108,19 @@ func collectionDetail(r *http.Request, q db.Queryer, col object) (object, error)
 		out[k] = v
 	}
 	out["properties"], out["views"], out["_count"] = props, views, counts
+	shared := str(col, "ownerId") != user(r)
+	out["shared"] = shared
+	if shared {
+		// Recipients see who shared it, but never the other recipients.
+		out["owner"], _ = db.One(r.Context(), q, `SELECT jsonb_build_object('id',u.id,'name',u.name,'email',u.email,'image',u.image) FROM "User" u WHERE u.id=$1`, str(col, "ownerId"))
+		out["sharedWith"] = []object{}
+	} else {
+		shares, e := db.Many(r.Context(), q, `SELECT jsonb_build_object('userId',s."userId",'email',u.email,'name',u.name,'createdAt',s."createdAt") FROM "CollectionShare" s JOIN "User" u ON u.id=s."userId" WHERE s."collectionId"=$1 ORDER BY s."createdAt"`, str(col, "id"))
+		if e != nil {
+			return nil, e
+		}
+		out["sharedWith"] = shares
+	}
 	return out, nil
 }
 
@@ -159,11 +181,18 @@ func HandleCollectionsList(w http.ResponseWriter, r *http.Request) {
 	// Item counts are authorized counts (N-10 edge case): a bookmark the
 	// caller can no longer see never inflates them. Collections are
 	// owner-scoped in phase 2, so $1 (owner) and $2 (BookmarkVisible) match.
-	v, e := db.Many(r.Context(), database(r), `SELECT to_jsonb(c)||jsonb_build_object('_count',jsonb_build_object(
+	// Owner collections and collections explicitly shared with this user.
+	// `shared` is disclosed by the UI; item counts are authorized counts and
+	// therefore only include bookmarks the caller may see.
+	v, e := db.Many(r.Context(), database(r), `SELECT to_jsonb(c)||jsonb_build_object(
+		'shared',c."ownerId"<>$1,
+		'owner',(SELECT jsonb_build_object('id',u.id,'name',u.name,'email',u.email,'image',u.image) FROM "User" u WHERE u.id=c."ownerId"),
+		'_count',jsonb_build_object(
 		'items',(SELECT count(*) FROM "CollectionItem" ci JOIN "Bookmark" b ON b.id=ci."bookmarkId" WHERE ci."collectionId"=c.id AND `+db.BookmarkVisible+`),
 		'properties',(SELECT count(*) FROM "CollectionProperty" p WHERE p."collectionId"=c.id),
 		'views',(SELECT count(*) FROM "CollectionView" v WHERE v."collectionId"=c.id)))
-		FROM "Collection" c WHERE c."ownerId"=$1 ORDER BY c."createdAt",c.id`, user(r), user(r))
+		FROM "Collection" c WHERE c."ownerId"=$1 OR EXISTS(SELECT 1 FROM "CollectionShare" s WHERE s."collectionId"=c.id AND s."userId"=$1)
+		ORDER BY (c."ownerId"<>$1),c."createdAt",c.id`, user(r), user(r))
 	respond(w, 200, v, e)
 }
 
@@ -204,7 +233,7 @@ func HandleCollectionsCreate(w http.ResponseWriter, r *http.Request) {
 }
 
 func HandleCollectionsGet(w http.ResponseWriter, r *http.Request) {
-	col, e := collectionOwned(r, database(r), r.PathValue("id"))
+	col, e := collectionReadable(r, database(r), r.PathValue("id"))
 	if e != nil {
 		respond(w, 0, nil, e)
 		return
@@ -252,8 +281,51 @@ func HandleCollectionsUpdate(w http.ResponseWriter, r *http.Request) {
 
 func HandleCollectionsDelete(w http.ResponseWriter, r *http.Request) {
 	// Memberships, properties and views cascade; bookmarks are never touched
-	// (N-01 acceptance criterion).
-	respond(w, 200, OK{true}, remove(r, "Collection", r.PathValue("id"), "ownerId"))
+	// (N-01 acceptance criterion). The collection structure is snapshotted for
+	// restore; shares are not, so a revoked grant never comes back.
+	e := db.Transaction(r.Context(), database(r), func(tx *sql.Tx) error {
+		if e := lockUser(r, tx); e != nil {
+			return e
+		}
+		return trashCollection(r, tx, r.PathValue("id"))
+	})
+	respond(w, 200, OK{true}, e)
+}
+
+// HandleCollectionShare grants read-only access to explicitly named users.
+// The share is disclosed in the collection UI and revocable; recipients get
+// the narrowed bookmark projection for member bookmarks and cannot mutate the
+// collection or its items. Sharing an already-shared user is idempotent.
+func HandleCollectionShare(w http.ResponseWriter, r *http.Request) {
+	id := r.PathValue("id")
+	if _, e := collectionOwned(r, database(r), id); e != nil {
+		respond(w, 0, nil, e)
+		return
+	}
+	b, ok := read(w, r)
+	if !ok {
+		return
+	}
+	list, e := ids(b, "userIds")
+	if e != nil {
+		respond(w, 0, nil, e)
+		return
+	}
+	// Sharing with yourself is meaningless; skip it rather than creating an
+	// ownership-adjacent row that would confuse the recipient list.
+	filtered := make([]string, 0, len(list))
+	for _, uid := range list {
+		if uid != user(r) {
+			filtered = append(filtered, uid)
+		}
+	}
+	e = db.Transaction(r.Context(), database(r), func(tx *sql.Tx) error {
+		if e := lockUser(r, tx); e != nil {
+			return e
+		}
+		return shareRows(r, tx, "CollectionShare", "collectionId", id, filtered)
+	})
+	respond(w, 200, OK{true}, e)
 }
 
 // --- properties -----------------------------------------------------------
@@ -1203,8 +1275,9 @@ func HandleCollectionItemsList(w http.ResponseWriter, r *http.Request) {
 		}
 		limit = n
 	}
-	// Ownership is the gate: a foreign collection is a 404, not an empty list.
-	if _, e := collectionOwned(r, database(r), cid); e != nil {
+	// Owner or explicit share is the read gate: a foreign collection is a
+	// 404, not an empty list. Mutations below still require ownership.
+	if _, e := collectionReadable(r, database(r), cid); e != nil {
 		respond(w, 0, nil, e)
 		return
 	}
@@ -1217,7 +1290,7 @@ func HandleCollectionItemsList(w http.ResponseWriter, r *http.Request) {
 	// $1 stays a permanently-nil placeholder (BookmarkVisible binds $2), the
 	// same port artifact the bookmarks list documents.
 	args := []any{nil, user(r), cid}
-	where := `c."ownerId"=$2 AND ci."collectionId"=$3 AND ` + db.BookmarkVisible + ` AND $1::text IS NULL`
+	where := `(c."ownerId"=$2 OR EXISTS(SELECT 1 FROM "CollectionShare" cs WHERE cs."collectionId"=c.id AND cs."userId"=$2)) AND ci."collectionId"=$3 AND ` + db.BookmarkVisible + ` AND $1::text IS NULL`
 	var sorts []any
 	if viewID := sp.Get("viewId"); viewID != "" {
 		view, e2 := db.One(r.Context(), database(r), `SELECT to_jsonb(v) FROM "CollectionView" v WHERE v.id=$1 AND v."collectionId"=$2`, viewID, cid)

internal/handlers/export.go

@@ -0,0 +1,83 @@
+package handlers
+
+import (
+	"net/http"
+	"time"
+
+	"github.com/andrew/go-computer/internal/db"
+)
+
+// Structured export (trust phase): a single owner-scoped JSON archive that is
+// richer than the per-item Markdown downloads. It deliberately excludes
+// credentials (IMAP config, CardDAV passwords) and includes only data the
+// caller owns or may read through the owner projection.
+func HandleExport(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	uid := user(r)
+	me, e := db.One(ctx, database(r), `SELECT jsonb_build_object('id',u.id,'name',u.name,'email',u.email,'role',u.role,'createdAt',u."createdAt") FROM "User" u WHERE u.id=$1`, uid)
+	if e != nil {
+		respond(w, 0, nil, e)
+		return
+	}
+	bookmarks, e := db.Many(ctx, database(r), `SELECT `+db.BookmarkOwnerView+` FROM "Bookmark" b WHERE b."ownerId"=$1 ORDER BY b."createdAt",b.id`, uid)
+	if e != nil {
+		respond(w, 0, nil, e)
+		return
+	}
+	tags, e := db.Many(ctx, database(r), `SELECT to_jsonb(t)||jsonb_build_object('sharedWith',COALESCE((SELECT jsonb_agg(jsonb_build_object('userId',s."userId",'email',u.email,'name',u.name)) FROM "TagShare" s JOIN "User" u ON u.id=s."userId" WHERE s."tagId"=t.id),'[]'::jsonb)) FROM "Tag" t WHERE t."ownerId"=$1 ORDER BY t."createdAt",t.id`, uid)
+	if e != nil {
+		respond(w, 0, nil, e)
+		return
+	}
+	pages, e := db.Many(ctx, database(r), `SELECT to_jsonb(p)||jsonb_build_object(
+		'bookmarks',COALESCE((SELECT jsonb_agg(to_jsonb(pb)||jsonb_build_object('bookmark',`+db.BookmarkOwnerView+`) ORDER BY pb.position) FROM "PageBookmark" pb JOIN "Bookmark" b ON b.id=pb."bookmarkId" WHERE pb."pageId"=p.id AND b."ownerId"=$1),'[]'::jsonb),
+		'revisions',COALESCE((SELECT jsonb_agg(to_jsonb(r) ORDER BY r.version) FROM "PageRevision" r WHERE r."pageId"=p.id),'[]'::jsonb))
+		FROM "Page" p WHERE p."ownerId"=$1 ORDER BY p."createdAt",p.id`, uid)
+	if e != nil {
+		respond(w, 0, nil, e)
+		return
+	}
+	contacts, e := db.Many(ctx, database(r), `SELECT to_jsonb(c) FROM "Contact" c WHERE c."userId"=$1 ORDER BY c."displayName",c.id`, uid)
+	if e != nil {
+		respond(w, 0, nil, e)
+		return
+	}
+	collections, e := db.Many(ctx, database(r), `SELECT to_jsonb(c) FROM "Collection" c WHERE c."ownerId"=$1 ORDER BY c."createdAt",c.id`, uid)
+	if e != nil {
+		respond(w, 0, nil, e)
+		return
+	}
+	exported := make([]object, 0, len(collections))
+	for _, col := range collections {
+		detail, e := collectionDetail(r, database(r), col)
+		if e != nil {
+			respond(w, 0, nil, e)
+			return
+		}
+		cid := str(col, "id")
+		items, e := db.Many(ctx, database(r), `SELECT to_jsonb(ci)||jsonb_build_object('bookmark',`+db.BookmarkOwnerView+`) FROM "CollectionItem" ci JOIN "Bookmark" b ON b.id=ci."bookmarkId" WHERE ci."collectionId"=$1 ORDER BY ci.position,ci.id`, cid)
+		if e != nil {
+			respond(w, 0, nil, e)
+			return
+		}
+		shares, e := db.Many(ctx, database(r), `SELECT jsonb_build_object('userId',s."userId",'email',u.email,'name',u.name,'createdAt',s."createdAt") FROM "CollectionShare" s JOIN "User" u ON u.id=s."userId" WHERE s."collectionId"=$1 ORDER BY s."createdAt"`, cid)
+		if e != nil {
+			respond(w, 0, nil, e)
+			return
+		}
+		detail["items"], detail["sharedWith"] = items, shares
+		exported = append(exported, detail)
+	}
+	w.Header().Set("Content-Disposition", `attachment; filename="computer-export.json"`)
+	respond(w, 200, object{
+		"format":      "computer-export",
+		"version":     1,
+		"exportedAt":  time.Now().UTC(),
+		"user":        me,
+		"bookmarks":   bookmarks,
+		"tags":        tags,
+		"pages":       pages,
+		"collections": exported,
+		"contacts":    contacts,
+	}, nil)
+}

internal/handlers/page_revisions.go

@@ -0,0 +1,95 @@
+package handlers
+
+import (
+	"database/sql"
+	"net/http"
+	"time"
+
+	"github.com/andrew/go-computer/internal/db"
+)
+
+// Page revision history (trust phase). Every committed content version gets
+// an immutable snapshot; restoring an old snapshot writes a new version rather
+// than rewriting history. Snapshots are owner-scoped through their page.
+func capturePageRevision(r *http.Request, tx *sql.Tx, pageID string) error {
+	_, e := tx.ExecContext(r.Context(), `INSERT INTO "PageRevision"(id,"pageId",version,title,content,icon)
+		SELECT $1,p.id,p.version,p.title,p.content,p.icon FROM "Page" p WHERE p.id=$2
+		ON CONFLICT ("pageId",version) DO NOTHING`, db.NewID(), pageID)
+	return e
+}
+
+func revisionOwned(r *http.Request, q db.Queryer, pageID, revisionID string) (object, error) {
+	if _, e := owned(r, q, "Page", pageID, "ownerId"); e != nil {
+		return nil, e
+	}
+	return db.One(r.Context(), q, `SELECT to_jsonb(r) FROM "PageRevision" r WHERE r.id=$1 AND r."pageId"=$2`, revisionID, pageID)
+}
+
+// HandlePageRevisionsList returns metadata only — the editor fetches a body on
+// demand (a page can have a long history and each body is up to 512 KiB).
+func HandlePageRevisionsList(w http.ResponseWriter, r *http.Request) {
+	pageID := r.PathValue("id")
+	if _, e := owned(r, database(r), "Page", pageID, "ownerId"); e != nil {
+		respond(w, 0, nil, e)
+		return
+	}
+	v, e := db.Many(r.Context(), database(r), `SELECT jsonb_build_object(
+		'id',r.id,'version',r.version,'title',r.title,'icon',r.icon,
+		'createdAt',r."createdAt",'length',length(r.content))
+		FROM "PageRevision" r WHERE r."pageId"=$1 ORDER BY r.version DESC`, pageID)
+	respond(w, 200, v, e)
+}
+
+func HandlePageRevisionsGet(w http.ResponseWriter, r *http.Request) {
+	v, e := revisionOwned(r, database(r), r.PathValue("id"), r.PathValue("revisionId"))
+	respond(w, 200, v, e)
+}
+
+// HandlePageRevisionsRestore copies a snapshot into the live page as a new
+// version. It requires the current base version (the same DATA-05 rule as a
+// content save), so restoring while another tab writes is a 409, not a silent
+// overwrite. The restored state itself becomes a history entry.
+func HandlePageRevisionsRestore(w http.ResponseWriter, r *http.Request) {
+	pageID, revisionID := r.PathValue("id"), r.PathValue("revisionId")
+	b, ok := read(w, r)
+	if !ok {
+		return
+	}
+	baseVersion, e := patchVersion(b)
+	if e != nil {
+		respond(w, 0, nil, e)
+		return
+	}
+	var v object
+	e = db.Transaction(r.Context(), database(r), func(tx *sql.Tx) error {
+		if e := lockUser(r, tx); e != nil {
+			return e
+		}
+		current, e := owned(r, tx, "Page", pageID, "ownerId")
+		if e != nil {
+			return e
+		}
+		if stored, _ := current["version"].(float64); int(stored) != baseVersion {
+			return conflict("Page was modified elsewhere; reload to see the latest version")
+		}
+		rev, e := db.One(r.Context(), tx, `SELECT to_jsonb(r) FROM "PageRevision" r WHERE r.id=$1 AND r."pageId"=$2`, revisionID, pageID)
+		if e != nil {
+			return e
+		}
+		if _, e := tx.ExecContext(r.Context(), `UPDATE "Page" SET title=$1,content=$2,icon=$3,version=version+1,"updatedAt"=$4 WHERE id=$5 AND "ownerId"=$6`,
+			str(rev, "title"), str(rev, "content"), rev["icon"], time.Now().UTC(), pageID, user(r)); e != nil {
+			return e
+		}
+		// Restoring content also restores its derived graph. Targets that no
+		// longer exist (or are no longer owned) are ignored by syncPageGraph.
+		if e := syncPageGraph(r.Context(), tx, pageID, user(r), str(rev, "content")); e != nil {
+			return e
+		}
+		if e := capturePageRevision(r, tx, pageID); e != nil {
+			return e
+		}
+		v, e = pageView(r.Context(), tx, pageID, user(r))
+		return e
+	})
+	respond(w, 200, v, e)
+}

internal/handlers/pages.go

@@ -121,6 +121,9 @@ func HandlePagesCreate(w http.ResponseWriter, r *http.Request) {
 				return e
 			}
 		}
+		if e := capturePageRevision(r, tx, d["id"].(string)); e != nil {
+			return e
+		}
 		// Acknowledge the same snapshot the write produced (the update path's
 		// CR-18 discipline), so the 201 already carries links/embeds.
 		v, e = pageView(r.Context(), tx, d["id"].(string), user(r))
@@ -218,6 +221,9 @@ func HandlePagesUpdate(w http.ResponseWriter, r *http.Request) {
 			if e := syncPageGraph(r.Context(), tx, id, user(r), content); e != nil {
 				return e
 			}
+			if e := capturePageRevision(r, tx, id); e != nil {
+				return e
+			}
 		}
 		if bid := str(b, "addBookmarkId"); bid != "" {
 			if _, e := db.One(r.Context(), tx, `SELECT to_jsonb(b) FROM "Bookmark" b WHERE b.id=$1 AND `+db.BookmarkVisible, bid, user(r)); e != nil {
@@ -254,8 +260,15 @@ func HandlePagesBacklinks(w http.ResponseWriter, r *http.Request) {
 }
 func HandlePagesDelete(w http.ResponseWriter, r *http.Request) {
 	// Children are promoted to the top level by the self-FK's SET NULL; a
-	// delete never silently takes nested pages with it.
-	respond(w, 200, OK{true}, remove(r, "Page", r.PathValue("id"), "ownerId"))
+	// delete never silently takes nested pages with it. The page, its history
+	// and its bookmark links are snapshotted for restore.
+	e := db.Transaction(r.Context(), database(r), func(tx *sql.Tx) error {
+		if e := lockUser(r, tx); e != nil {
+			return e
+		}
+		return trashPage(r, tx, r.PathValue("id"))
+	})
+	respond(w, 200, OK{true}, e)
 }
 func HandlePagesMarkdown(w http.ResponseWriter, r *http.Request) {
 	v, e := page(r, r.PathValue("id"))

internal/handlers/trash.go

@@ -0,0 +1,364 @@
+package handlers
+
+import (
+	"database/sql"
+	"encoding/json"
+	"net/http"
+
+	"github.com/andrew/go-computer/internal/db"
+)
+
+// Recoverable deletions (trust phase).
+//
+// Trash stores a private, per-owner JSON snapshot taken in the same
+// transaction as the hard delete. Restoring inserts the intrinsic record and
+// owner-scoped relationships, but deliberately NOT access grants:
+//   - bookmark isPublic is forced false and bookmark/tag shares are not
+//     snapshotted, so a restored bookmark never resurrects a public link or a
+//     share removed while it was in the trash;
+//   - collection shares are not snapshotted;
+//   - server-driven watcher rows are not snapshotted.
+// Contextual collection memberships and page links are owner-scoped data and
+// are restored when their parent still exists.
+
+func jsonSnapshot(v any) (string, error) {
+	raw, e := json.Marshal(v)
+	return string(raw), e
+}
+
+func addTrash(r *http.Request, tx *sql.Tx, kind, originalID string, data object) error {
+	raw, e := jsonSnapshot(data)
+	if e != nil {
+		return e
+	}
+	_, e = db.Insert(r.Context(), tx, "Trash", object{
+		"id": db.NewID(), "ownerId": user(r), "type": kind,
+		"originalId": originalID, "data": raw,
+	})
+	return e
+}
+
+func deleteOwnedRow(r *http.Request, tx *sql.Tx, table, id, ownerCol string, deleted *int64) error {
+	res, e := tx.ExecContext(r.Context(), `DELETE FROM `+db.Quote(table)+` WHERE id=$1 AND `+db.Quote(ownerCol)+`=$2`, id, user(r))
+	if e != nil {
+		return e
+	}
+	n, _ := res.RowsAffected()
+	if n == 0 {
+		return db.ErrNotFound
+	}
+	if deleted != nil {
+		*deleted = n
+	}
+	return nil
+}
+
+// --- delete snapshots -----------------------------------------------------
+
+func trashBookmark(r *http.Request, tx *sql.Tx, id string) error {
+	row, e := owned(r, tx, "Bookmark", id, "ownerId")
+	if e != nil {
+		return e
+	}
+	tags, e := db.Many(r.Context(), tx, `SELECT jsonb_build_object('tagId',bt."tagId") FROM "BookmarkTag" bt JOIN "Tag" t ON t.id=bt."tagId" WHERE bt."bookmarkId"=$1 AND (t."ownerId"=$2 OR EXISTS(SELECT 1 FROM "TagShare" s WHERE s."tagId"=t.id AND s."userId"=$2))`, id, user(r))
+	if e != nil {
+		return e
+	}
+	pageLinks, e := db.Many(r.Context(), tx, `SELECT jsonb_build_object('pageId',pb."pageId",'position',pb.position) FROM "PageBookmark" pb JOIN "Page" p ON p.id=pb."pageId" WHERE pb."bookmarkId"=$1 AND p."ownerId"=$2`, id, user(r))
+	if e != nil {
+		return e
+	}
+	collectionItems, e := db.Many(r.Context(), tx, `SELECT jsonb_build_object('id',ci.id,'collectionId',ci."collectionId",'bookmarkId',ci."bookmarkId",'propertyValues',ci."propertyValues",'position',ci.position,'version',ci.version,'addedAt',ci."addedAt",'updatedAt',ci."updatedAt") FROM "CollectionItem" ci JOIN "Collection" c ON c.id=ci."collectionId" WHERE ci."bookmarkId"=$1 AND c."ownerId"=$2`, id, user(r))
+	if e != nil {
+		return e
+	}
+	if e := addTrash(r, tx, "bookmark", id, object{
+		"bookmark": row, "tags": tags, "pageLinks": pageLinks, "collectionItems": collectionItems,
+	}); e != nil {
+		return e
+	}
+	return deleteOwnedRow(r, tx, "Bookmark", id, "ownerId", nil)
+}
+
+func trashPage(r *http.Request, tx *sql.Tx, id string) error {
+	row, e := owned(r, tx, "Page", id, "ownerId")
+	if e != nil {
+		return e
+	}
+	bookmarks, e := db.Many(r.Context(), tx, `SELECT jsonb_build_object('bookmarkId',pb."bookmarkId",'position',pb.position) FROM "PageBookmark" pb WHERE pb."pageId"=$1`, id)
+	if e != nil {
+		return e
+	}
+	revisions, e := db.Many(r.Context(), tx, `SELECT to_jsonb(r) FROM "PageRevision" r WHERE r."pageId"=$1 ORDER BY r.version`, id)
+	if e != nil {
+		return e
+	}
+	if e := addTrash(r, tx, "page", id, object{"page": row, "bookmarks": bookmarks, "revisions": revisions}); e != nil {
+		return e
+	}
+	return deleteOwnedRow(r, tx, "Page", id, "ownerId", nil)
+}
+
+func trashCollection(r *http.Request, tx *sql.Tx, id string) error {
+	row, e := owned(r, tx, "Collection", id, "ownerId")
+	if e != nil {
+		return e
+	}
+	properties, e := db.Many(r.Context(), tx, `SELECT to_jsonb(p) FROM "CollectionProperty" p WHERE p."collectionId"=$1 ORDER BY p.position,p.id`, id)
+	if e != nil {
+		return e
+	}
+	views, e := db.Many(r.Context(), tx, `SELECT to_jsonb(v) FROM "CollectionView" v WHERE v."collectionId"=$1 ORDER BY v.position,v.id`, id)
+	if e != nil {
+		return e
+	}
+	items, e := db.Many(r.Context(), tx, `SELECT to_jsonb(ci) FROM "CollectionItem" ci WHERE ci."collectionId"=$1 ORDER BY ci.position,ci.id`, id)
+	if e != nil {
+		return e
+	}
+	if e := addTrash(r, tx, "collection", id, object{
+		"collection": row, "properties": properties, "views": views, "items": items,
+	}); e != nil {
+		return e
+	}
+	return deleteOwnedRow(r, tx, "Collection", id, "ownerId", nil)
+}
+
+// --- restore --------------------------------------------------------------
+
+func objectValue(v any) object {
+	if m, ok := v.(map[string]any); ok {
+		return m
+	}
+	return nil
+}
+
+func objectList(v any) []object {
+	arr, _ := v.([]any)
+	out := make([]object, 0, len(arr))
+	for _, x := range arr {
+		if m, ok := x.(map[string]any); ok {
+			out = append(out, m)
+		}
+	}
+	return out
+}
+
+func insertSnapshot(r *http.Request, tx *sql.Tx, table, kind string, row object) error {
+	raw, e := jsonSnapshot(row)
+	if e != nil {
+		return e
+	}
+	_, e = tx.ExecContext(r.Context(), `INSERT INTO `+db.Quote(table)+` SELECT * FROM jsonb_populate_record(NULL::`+db.Quote(table)+`, $1::jsonb)`, raw)
+	return e
+}
+
+func restoreBookmark(r *http.Request, tx *sql.Tx, data object) (string, error) {
+	row := objectValue(data["bookmark"])
+	if row == nil {
+		return "", bad("Trash entry is damaged")
+	}
+	id := str(row, "id")
+	// Restore access decisions to their safe default. A public link or a
+	// direct share is a grant, not intrinsic content.
+	row["isPublic"] = false
+	for _, pair := range [][2]string{{"contactId", "Contact"}, {"kanbanColumnId", "KanbanColumn"}} {
+		if ref := str(row, pair[0]); ref != "" {
+			col := "userId"
+			var exists bool
+			if e := tx.QueryRowContext(r.Context(), `SELECT EXISTS(SELECT 1 FROM `+db.Quote(pair[1])+` WHERE id=$1 AND `+db.Quote(col)+`=$2)`, ref, user(r)).Scan(&exists); e != nil {
+				return "", e
+			}
+			if !exists {
+				row[pair[0]] = nil
+			}
+		}
+	}
+	if e := insertSnapshot(r, tx, "Bookmark", "bookmark", row); e != nil {
+		return "", e
+	}
+	for _, t := range objectList(data["tags"]) {
+		tagID := str(t, "tagId")
+		var exists bool
+		if e := tx.QueryRowContext(r.Context(), `SELECT EXISTS(SELECT 1 FROM "Tag" t WHERE t.id=$1 AND (t."ownerId"=$2 OR EXISTS(SELECT 1 FROM "TagShare" s WHERE s."tagId"=t.id AND s."userId"=$2)))`, tagID, user(r)).Scan(&exists); e != nil {
+			return "", e
+		}
+		if exists {
+			if _, e := tx.ExecContext(r.Context(), `INSERT INTO "BookmarkTag"("bookmarkId","tagId") VALUES($1,$2) ON CONFLICT DO NOTHING`, id, tagID); e != nil {
+				return "", e
+			}
+		}
+	}
+	for _, l := range objectList(data["pageLinks"]) {
+		var exists bool
+		if e := tx.QueryRowContext(r.Context(), `SELECT EXISTS(SELECT 1 FROM "Page" WHERE id=$1 AND "ownerId"=$2)`, str(l, "pageId"), user(r)).Scan(&exists); e != nil {
+			return "", e
+		}
+		if !exists {
+			continue
+		}
+		if _, e := tx.ExecContext(r.Context(), `INSERT INTO "PageBookmark"("pageId","bookmarkId",position) VALUES($1,$2,$3) ON CONFLICT DO NOTHING`, str(l, "pageId"), id, intFieldValue(l, "position")); e != nil {
+			return "", e
+		}
+	}
+	for _, item := range objectList(data["collectionItems"]) {
+		var exists bool
+		if e := tx.QueryRowContext(r.Context(), `SELECT EXISTS(SELECT 1 FROM "Collection" WHERE id=$1 AND "ownerId"=$2)`, str(item, "collectionId"), user(r)).Scan(&exists); e != nil {
+			return "", e
+		}
+		if !exists {
+			continue
+		}
+		if e := insertSnapshot(r, tx, "CollectionItem", "collectionItem", item); e != nil {
+			return "", e
+		}
+	}
+	return id, nil
+}
+
+func intFieldValue(b object, key string) int {
+	if f, ok := b[key].(float64); ok {
+		return int(f)
+	}
+	return 0
+}
+
+func restorePage(r *http.Request, tx *sql.Tx, data object) (string, error) {
+	row := objectValue(data["page"])
+	if row == nil {
+		return "", bad("Trash entry is damaged")
+	}
+	id := str(row, "id")
+	parent, e := pageParent(r.Context(), tx, id, user(r), row["parentId"])
+	if e != nil {
+		// A parent deleted while this page sat in the trash simply promotes
+		// the restored page to the top level.
+		if _, ok := e.(clientError); !ok {
+			return "", e
+		}
+		parent = nil
+	}
+	row["parentId"] = parent
+	if e := insertSnapshot(r, tx, "Page", "page", row); e != nil {
+		return "", e
+	}
+	for _, l := range objectList(data["bookmarks"]) {
+		var visible bool
+		if e := tx.QueryRowContext(r.Context(), `SELECT EXISTS(SELECT 1 FROM "Bookmark" b WHERE b.id=$1 AND `+db.BookmarkVisible+`)`, str(l, "bookmarkId"), user(r)).Scan(&visible); e != nil {
+			return "", e
+		}
+		if !visible {
+			continue
+		}
+		if _, e := tx.ExecContext(r.Context(), `INSERT INTO "PageBookmark"("pageId","bookmarkId",position) VALUES($1,$2,$3) ON CONFLICT DO NOTHING`, id, str(l, "bookmarkId"), intFieldValue(l, "position")); e != nil {
+			return "", e
+		}
+	}
+	for _, rev := range objectList(data["revisions"]) {
+		if e := insertSnapshot(r, tx, "PageRevision", "pageRevision", rev); e != nil {
+			return "", e
+		}
+	}
+	if e := syncPageGraph(r.Context(), tx, id, user(r), str(row, "content")); e != nil {
+		return "", e
+	}
+	// A restore is a new trust event: bump the revision and record it, so the
+	// state that came back from the trash is itself auditable.
+	if _, e := tx.ExecContext(r.Context(), `UPDATE "Page" SET version=version+1,"updatedAt"=now() WHERE id=$1 AND "ownerId"=$2`, id, user(r)); e != nil {
+		return "", e
+	}
+	if e := capturePageRevision(r, tx, id); e != nil {
+		return "", e
+	}
+	return id, nil
+}
+
+func restoreCollection(r *http.Request, tx *sql.Tx, data object) (string, error) {
+	row := objectValue(data["collection"])
+	if row == nil {
+		return "", bad("Trash entry is damaged")
+	}
+	id := str(row, "id")
+	if e := insertSnapshot(r, tx, "Collection", "collection", row); e != nil {
+		return "", e
+	}
+	for _, prop := range objectList(data["properties"]) {
+		if e := insertSnapshot(r, tx, "CollectionProperty", "collectionProperty", prop); e != nil {
+			return "", e
+		}
+	}
+	for _, view := range objectList(data["views"]) {
+		if e := insertSnapshot(r, tx, "CollectionView", "collectionView", view); e != nil {
+			return "", e
+		}
+	}
+	for _, item := range objectList(data["items"]) {
+		var visible bool
+		if e := tx.QueryRowContext(r.Context(), `SELECT EXISTS(SELECT 1 FROM "Bookmark" b WHERE b.id=$1 AND `+db.BookmarkVisible+`)`, str(item, "bookmarkId"), user(r)).Scan(&visible); e != nil {
+			return "", e
+		}
+		if !visible {
+			continue
+		}
+		if e := insertSnapshot(r, tx, "CollectionItem", "collectionItem", item); e != nil {
+			return "", e
+		}
+	}
+	return id, nil
+}
+
+// --- HTTP surfaces --------------------------------------------------------
+
+func HandleTrashList(w http.ResponseWriter, r *http.Request) {
+	v, e := db.Many(r.Context(), database(r), `SELECT jsonb_build_object(
+		'id',t.id,'type',t.type,'originalId',t."originalId",'deletedAt',t."deletedAt",
+		'title',COALESCE(
+			NULLIF(t.data->'bookmark'->>'title',''),
+			t.data->'bookmark'->>'url',
+			NULLIF(t.data->'page'->>'title',''),
+			t.data->'collection'->>'name',
+			'Untitled'))
+		FROM "Trash" t WHERE t."ownerId"=$1 ORDER BY t."deletedAt" DESC,t.id`, user(r))
+	respond(w, 200, v, e)
+}
+
+func HandleTrashRestore(w http.ResponseWriter, r *http.Request) {
+	id := r.PathValue("id")
+	var kind, originalID string
+	e := db.Transaction(r.Context(), database(r), func(tx *sql.Tx) error {
+		if e := lockUser(r, tx); e != nil {
+			return e
+		}
+		entry, e := db.One(r.Context(), tx, `SELECT to_jsonb(t) FROM "Trash" t WHERE t.id=$1 AND t."ownerId"=$2 FOR UPDATE`, id, user(r))
+		if e != nil {
+			return e
+		}
+		kind, originalID = str(entry, "type"), str(entry, "originalId")
+		data := objectValue(entry["data"])
+		if data == nil {
+			return bad("Trash entry is damaged")
+		}
+		switch kind {
+		case "bookmark":
+			_, e = restoreBookmark(r, tx, data)
+		case "page":
+			_, e = restorePage(r, tx, data)
+		case "collection":
+			_, e = restoreCollection(r, tx, data)
+		default:
+			return bad("Unknown trash entry type")
+		}
+		if e != nil {
+			return e
+		}
+		_, e = tx.ExecContext(r.Context(), `DELETE FROM "Trash" WHERE id=$1 AND "ownerId"=$2`, id, user(r))
+		return e
+	})
+	respond(w, 200, object{"ok": true, "type": kind, "id": originalID}, e)
+}
+
+func HandleTrashPurge(w http.ResponseWriter, r *http.Request) {
+	// Permanent removal is explicit (the default delete moves to the trash).
+	_, e := database(r).ExecContext(r.Context(), `DELETE FROM "Trash" WHERE id=$1 AND "ownerId"=$2`, r.PathValue("id"), user(r))
+	respond(w, 200, OK{true}, e)
+}

internal/handlers/unshare.go

@@ -20,6 +20,9 @@ func HandleBookmarkUnshare(w http.ResponseWriter, r *http.Request) {
 func HandleTagUnshare(w http.ResponseWriter, r *http.Request) {
 	unshare(w, r, "Tag", "TagShare", "tagId")
 }
+func HandleCollectionUnshare(w http.ResponseWriter, r *http.Request) {
+	unshare(w, r, "Collection", "CollectionShare", "collectionId")
+}
 func HandleSharedDateDelete(w http.ResponseWriter, r *http.Request) {
 	respond(w, 200, OK{true}, remove(r, "SharedDate", r.PathValue("id"), "creatorId"))
 }

internal/http/server.go

@@ -89,8 +89,17 @@ func NewServer(cfg *config.Config, database *db.DB) *http.Server {
 	mux.HandleFunc("PATCH /api/pages/{id}", authed(handlers.HandlePagesUpdate))
 	mux.HandleFunc("DELETE /api/pages/{id}", authed(handlers.HandlePagesDelete))
 	mux.HandleFunc("GET /api/pages/{id}/backlinks", authed(handlers.HandlePagesBacklinks))
+	mux.HandleFunc("GET /api/pages/{id}/revisions", authed(handlers.HandlePageRevisionsList))
+	mux.HandleFunc("GET /api/pages/{id}/revisions/{revisionId}", authed(handlers.HandlePageRevisionsGet))
+	mux.HandleFunc("POST /api/pages/{id}/revisions/{revisionId}/restore", authed(handlers.HandlePageRevisionsRestore))
 	mux.HandleFunc("GET /api/pages/{id}/markdown", authed(handlers.HandlePagesMarkdown))
 
+	// Trust phase: recoverable deletions and structured export.
+	mux.HandleFunc("GET /api/trash", authed(handlers.HandleTrashList))
+	mux.HandleFunc("POST /api/trash/{id}/restore", authed(handlers.HandleTrashRestore))
+	mux.HandleFunc("DELETE /api/trash/{id}", authed(handlers.HandleTrashPurge))
+	mux.HandleFunc("GET /api/export", authed(handlers.HandleExport))
+
 	// 4.7 Signals
 	mux.HandleFunc("GET /api/bookmarks/{id}/signals", authed(handlers.HandleSignalsList))
 	mux.HandleFunc("POST /api/bookmarks/{id}/signals", authed(handlers.HandleSignalsCreate))
@@ -118,6 +127,8 @@ func NewServer(cfg *config.Config, database *db.DB) *http.Server {
 	mux.HandleFunc("GET /api/collections/{id}", authed(handlers.HandleCollectionsGet))
 	mux.HandleFunc("PATCH /api/collections/{id}", authed(handlers.HandleCollectionsUpdate))
 	mux.HandleFunc("DELETE /api/collections/{id}", authed(handlers.HandleCollectionsDelete))
+	mux.HandleFunc("POST /api/collections/{id}/share", authed(handlers.HandleCollectionShare))
+	mux.HandleFunc("DELETE /api/collections/{id}/share/{userId}", authed(handlers.HandleCollectionUnshare))
 	mux.HandleFunc("POST /api/collections/{id}/properties", authed(handlers.HandleCollectionPropertiesCreate))
 	mux.HandleFunc("PATCH /api/collections/{id}/properties/{propertyId}", authed(handlers.HandleCollectionPropertiesUpdate))
 	mux.HandleFunc("DELETE /api/collections/{id}/properties/{propertyId}", authed(handlers.HandleCollectionPropertiesDelete))

internal/http/trust_test.go

@@ -0,0 +1,281 @@
+package http
+
+import (
+	"testing"
+)
+
+// Trust phase: page revision history, recoverable deletions that never
+// resurrect access grants, structured export, and explicit collection sharing.
+
+func TestPageRevisionHistory(t *testing.T) {
+	srv := testServer(t)
+	alice := newAPIUser(t, srv, "trust-history@computer.test")
+	bob := newAPIUser(t, srv, "trust-history-other@computer.test")
+
+	page := alice.request("POST", "/api/pages", map[string]any{"title": "History", "content": "version one"}, 201)["id"].(string)
+	revisions := alice.getJSON("/api/pages/"+page+"/revisions", 200)
+	if len(revisions) != 1 || revisions[0]["version"].(float64) != 1 || revisions[0]["content"] != nil {
+		t.Fatalf("initial revision metadata: %v", revisions)
+	}
+	first := revisions[0]["id"].(string)
+	body := alice.request("GET", "/api/pages/"+page+"/revisions/"+first, nil, 200)
+	if body["content"] != "version one" {
+		t.Fatalf("revision body: %v", body)
+	}
+
+	alice.request("PATCH", "/api/pages/"+page, map[string]any{"content": "version two", "version": 1}, 200)
+	revisions = alice.getJSON("/api/pages/"+page+"/revisions", 200)
+	if len(revisions) != 2 || revisions[0]["version"].(float64) != 2 {
+		t.Fatalf("history did not append: %v", revisions)
+	}
+
+	// Restore writes a NEW version rather than rewriting history.
+	restored := alice.request("POST", "/api/pages/"+page+"/revisions/"+first+"/restore", map[string]any{"version": 2}, 200)
+	if restored["content"] != "version one" || restored["version"].(float64) != 3 {
+		t.Fatalf("restore did not create a new version: %v", restored)
+	}
+	revisions = alice.getJSON("/api/pages/"+page+"/revisions", 200)
+	if len(revisions) != 3 || revisions[0]["version"].(float64) != 3 {
+		t.Fatalf("restore was not recorded as history: %v", revisions)
+	}
+	if got := alice.request("GET", "/api/pages/"+page+"/revisions/"+revisions[0]["id"].(string), nil, 200); got["content"] != "version one" {
+		t.Fatalf("restored revision body: %v", got)
+	}
+
+	// A stale base is a 409, not a silent overwrite.
+	alice.request("POST", "/api/pages/"+page+"/revisions/"+first+"/restore", map[string]any{"version": 2}, 409)
+	alice.request("POST", "/api/pages/"+page+"/revisions/"+first+"/restore", map[string]any{}, 400)
+	bob.request("GET", "/api/pages/"+page+"/revisions", nil, 404)
+	bob.request("GET", "/api/pages/"+page+"/revisions/"+first, nil, 404)
+	bob.request("POST", "/api/pages/"+page+"/revisions/"+first+"/restore", map[string]any{"version": 3}, 404)
+}
+
+func TestTrashRestoreNeverResurrectsGrants(t *testing.T) {
+	srv := testServer(t)
+	alice := newAPIUser(t, srv, "trust-trash@computer.test")
+	bob := newAPIUser(t, srv, "trust-trash-other@computer.test")
+	bobID := meID(bob)
+
+	tag := alice.request("POST", "/api/tags", map[string]any{"name": "Restored tag"}, 201)["id"].(string)
+	page := alice.request("POST", "/api/pages", map[string]any{"title": "Host page"}, 201)["id"].(string)
+	col := alice.request("POST", "/api/collections", map[string]any{"name": "Restored project"}, 201)
+	cid := col["id"].(string)
+	prop := alice.request("POST", "/api/collections/"+cid+"/properties", map[string]any{"name": "Status", "type": "TEXT"}, 201)["id"].(string)
+
+	bm := alice.request("POST", "/api/bookmarks", map[string]any{
+		"url": "https://127.0.0.1/restore-me", "title": "Restore me", "tagIds": []string{tag}, "isPublic": true,
+	}, 201)
+	bid := bm["id"].(string)
+	alice.request("PATCH", "/api/pages/"+page, map[string]any{"addBookmarkId": bid}, 200)
+	alice.request("POST", "/api/collections/"+cid+"/items", map[string]any{"bookmarkId": bid, "propertyValues": map[string]any{prop: "kept"}}, 201)
+	alice.request("POST", "/api/bookmarks/"+bid+"/share", map[string]any{"userIds": []string{bobID}}, 200)
+	bob.request("GET", "/api/bookmarks/"+bid, nil, 200)
+	alice.request("GET", "/api/public/bookmarks/"+bid, nil, 200)
+
+	alice.request("DELETE", "/api/bookmarks/"+bid, nil, 200)
+	bob.request("GET", "/api/bookmarks/"+bid, nil, 404)
+	alice.request("GET", "/api/public/bookmarks/"+bid, nil, 404)
+	trash := alice.getJSON("/api/trash", 200)
+	if len(trash) != 1 || trash[0]["type"] != "bookmark" || trash[0]["title"] != "Restore me" {
+		t.Fatalf("bookmark trash entry: %v", trash)
+	}
+	entry := trash[0]["id"].(string)
+	bob.request("POST", "/api/trash/"+entry+"/restore", map[string]any{}, 404)
+
+	restored := alice.request("POST", "/api/trash/"+entry+"/restore", map[string]any{}, 200)
+	if restored["ok"] != true || restored["id"] != bid {
+		t.Fatalf("restore response: %v", restored)
+	}
+	// Intrinsic links return; access grants do not.
+	got := alice.request("GET", "/api/bookmarks/"+bid, nil, 200)
+	if got["title"] != "Restore me" || len(got["tags"].([]any)) != 1 || got["isPublic"] != false {
+		t.Fatalf("restored bookmark: %v", got)
+	}
+	if len(got["pageLinks"].([]any)) != 1 {
+		t.Fatalf("page link was not restored: %v", got["pageLinks"])
+	}
+	bob.request("GET", "/api/bookmarks/"+bid, nil, 404)
+	alice.request("GET", "/api/public/bookmarks/"+bid, nil, 404)
+	items := alice.getJSON("/api/collections/"+cid+"/items", 200)
+	if len(items) != 1 || items[0]["propertyValues"].(map[string]any)[prop] != "kept" {
+		t.Fatalf("collection membership was not restored: %v", items)
+	}
+	if trash := alice.getJSON("/api/trash", 200); len(trash) != 0 {
+		t.Fatalf("restored entry stayed in trash: %v", trash)
+	}
+
+	// Pages restore with their history, and the restore is itself a revision.
+	alice.request("PATCH", "/api/pages/"+page, map[string]any{"content": "page body", "version": 1}, 200)
+	alice.request("DELETE", "/api/pages/"+page, nil, 200)
+	alice.request("GET", "/api/pages/"+page, nil, 404)
+	trash = alice.getJSON("/api/trash", 200)
+	var pageEntry string
+	for _, row := range trash {
+		if row["type"] == "page" {
+			pageEntry = row["id"].(string)
+		}
+	}
+	if pageEntry == "" {
+		t.Fatalf("page missing from trash: %v", trash)
+	}
+	alice.request("POST", "/api/trash/"+pageEntry+"/restore", map[string]any{}, 200)
+	restoredPage := alice.request("GET", "/api/pages/"+page, nil, 200)
+	if restoredPage["content"] != "page body" || len(restoredPage["bookmarks"].([]any)) != 1 {
+		t.Fatalf("restored page: %v", restoredPage)
+	}
+	revs := alice.getJSON("/api/pages/"+page+"/revisions", 200)
+	if len(revs) < 3 {
+		t.Fatalf("page history was not restored/extended: %v", revs)
+	}
+	if revs[0]["version"].(float64) != restoredPage["version"].(float64) {
+		t.Fatalf("restore revision is not the current version: revs=%v page=%v", revs[0], restoredPage["version"])
+	}
+
+	// Collections restore structure and items; prior shares do not come back.
+	alice.request("POST", "/api/collections/"+cid+"/share", map[string]any{"userIds": []string{bobID}}, 200)
+	bob.request("GET", "/api/collections/"+cid, nil, 200)
+	alice.request("DELETE", "/api/collections/"+cid, nil, 200)
+	bob.request("GET", "/api/collections/"+cid, nil, 404)
+	trash = alice.getJSON("/api/trash", 200)
+	var collectionEntry string
+	for _, row := range trash {
+		if row["type"] == "collection" {
+			collectionEntry = row["id"].(string)
+		}
+	}
+	if collectionEntry == "" {
+		t.Fatalf("collection missing from trash: %v", trash)
+	}
+	alice.request("POST", "/api/trash/"+collectionEntry+"/restore", map[string]any{}, 200)
+	detail := alice.request("GET", "/api/collections/"+cid, nil, 200)
+	if detail["name"] != "Restored project" || len(detail["properties"].([]any)) != 1 {
+		t.Fatalf("restored collection: %v", detail)
+	}
+	if items := alice.getJSON("/api/collections/"+cid+"/items", 200); len(items) != 1 {
+		t.Fatalf("restored collection items: %v", items)
+	}
+	bob.request("GET", "/api/collections/"+cid, nil, 404)
+
+	// Permanent purge is explicit and owner-scoped.
+	alice.request("POST", "/api/trash/"+entry+"/restore", map[string]any{}, 404)
+}
+
+func TestCollectionSharingPermissionBoundary(t *testing.T) {
+	srv := testServer(t)
+	alice := newAPIUser(t, srv, "trust-coll-share@computer.test")
+	bob := newAPIUser(t, srv, "trust-coll-recipient@computer.test")
+	carol := newAPIUser(t, srv, "trust-coll-third@computer.test")
+	bobID, carolID := meID(bob), meID(carol)
+
+	bm := alice.request("POST", "/api/bookmarks", map[string]any{"url": "https://127.0.0.1/collection-share", "title": "Shared via project", "notes": "secret owner notes", "isPublic": true}, 201)
+	bid := bm["id"].(string)
+	col := alice.request("POST", "/api/collections", map[string]any{"name": "Team project"}, 201)
+	cid := col["id"].(string)
+	prop := alice.request("POST", "/api/collections/"+cid+"/properties", map[string]any{"name": "Status", "type": "TEXT"}, 201)["id"].(string)
+	alice.request("POST", "/api/collections/"+cid+"/items", map[string]any{"bookmarkId": bid, "propertyValues": map[string]any{prop: "Doing"}}, 201)
+
+	bob.request("GET", "/api/collections/"+cid, nil, 404)
+	bob.request("GET", "/api/bookmarks/"+bid, nil, 404)
+	alice.request("POST", "/api/collections/"+cid+"/share", map[string]any{"userIds": []string{bobID}}, 200)
+
+	// Owner sees the disclosure.
+	detail := alice.request("GET", "/api/collections/"+cid, nil, 200)
+	if detail["shared"] != false || len(detail["sharedWith"].([]any)) != 1 {
+		t.Fatalf("owner share disclosure: %v", detail)
+	}
+	// Recipient sees the collection, its items, and the narrowed bookmark
+	// projection — never the owner's contact/share/recipient metadata.
+	listed := bob.getJSON("/api/collections", 200)
+	found := false
+	for _, c := range listed {
+		if c["id"] == cid {
+			found = c["shared"] == true
+		}
+	}
+	if !found {
+		t.Fatalf("shared collection missing from recipient list: %v", listed)
+	}
+	bobDetail := bob.request("GET", "/api/collections/"+cid, nil, 200)
+	if bobDetail["shared"] != true || len(bobDetail["sharedWith"].([]any)) != 0 {
+		t.Fatalf("recipient detail disclosure: %v", bobDetail)
+	}
+	items := bob.getJSON("/api/collections/"+cid+"/items", 200)
+	if len(items) != 1 || items[0]["propertyValues"].(map[string]any)[prop] != "Doing" {
+		t.Fatalf("recipient items: %v", items)
+	}
+	sharedBookmark := bob.request("GET", "/api/bookmarks/"+bid, nil, 200)
+	if sharedBookmark["title"] != "Shared via project" || sharedBookmark["notes"] != "secret owner notes" {
+		t.Fatalf("recipient bookmark projection: %v", sharedBookmark)
+	}
+	if _, leaked := sharedBookmark["sharedWith"]; leaked {
+		t.Fatalf("recipient saw the owner's recipient list: %v", sharedBookmark)
+	}
+
+	// Read-only: mutations remain owner-only, including membership changes.
+	bob.request("PATCH", "/api/collections/"+cid, map[string]any{"version": 1, "name": "hijack"}, 404)
+	bob.request("DELETE", "/api/collections/"+cid, nil, 404)
+	bob.request("POST", "/api/collections/"+cid+"/items", map[string]any{"bookmarkId": bid}, 404)
+	bob.request("PATCH", "/api/collections/"+cid+"/items/"+items[0]["id"].(string), map[string]any{"version": 1, "propertyValues": map[string]any{prop: "Hijacked"}}, 404)
+	bob.request("POST", "/api/collections/"+cid+"/share", map[string]any{"userIds": []string{carolID}}, 404)
+	bob.request("DELETE", "/api/collections/"+cid+"/share/"+bobID, nil, 404)
+
+	// Revocation removes collection and bookmark access immediately.
+	alice.request("DELETE", "/api/collections/"+cid+"/share/"+bobID, nil, 200)
+	bob.request("GET", "/api/collections/"+cid, nil, 404)
+	bob.request("GET", "/api/collections/"+cid+"/items", nil, 404)
+	bob.request("GET", "/api/bookmarks/"+bid, nil, 404)
+
+	// Removing an item also removes the implicit bookmark grant.
+	alice.request("POST", "/api/collections/"+cid+"/share", map[string]any{"userIds": []string{bobID}}, 200)
+	bob.request("GET", "/api/bookmarks/"+bid, nil, 200)
+	alice.request("DELETE", "/api/collections/"+cid+"/items/"+items[0]["id"].(string), nil, 200)
+	bob.request("GET", "/api/bookmarks/"+bid, nil, 404)
+
+	// Transitive leaks are refused: Carol can see Alice's bookmark only because
+	// Alice shared it with Carol. Carol's collection share must not pass that
+	// grant on to Bob.
+	thirdParty := alice.request("POST", "/api/bookmarks", map[string]any{"url": "https://127.0.0.1/third-party", "title": "Alice's private link"}, 201)["id"].(string)
+	alice.request("POST", "/api/bookmarks/"+thirdParty+"/share", map[string]any{"userIds": []string{carolID}}, 200)
+	carol.request("GET", "/api/bookmarks/"+thirdParty, nil, 200)
+	carolCol := carol.request("POST", "/api/collections", map[string]any{"name": "Carol's project"}, 201)["id"].(string)
+	carol.request("POST", "/api/collections/"+carolCol+"/items", map[string]any{"bookmarkId": thirdParty}, 201)
+	carol.request("POST", "/api/collections/"+carolCol+"/share", map[string]any{"userIds": []string{bobID}}, 200)
+	bob.request("GET", "/api/collections/"+carolCol, nil, 200)
+	if leakedItems := bob.getJSON("/api/collections/"+carolCol+"/items", 200); len(leakedItems) != 0 {
+		t.Fatalf("collection share leaked a third-party bookmark: %v", leakedItems)
+	}
+	bob.request("GET", "/api/bookmarks/"+thirdParty, nil, 404)
+}
+
+func TestStructuredExport(t *testing.T) {
+	srv := testServer(t)
+	alice := newAPIUser(t, srv, "trust-export@computer.test")
+
+	tag := alice.request("POST", "/api/tags", map[string]any{"name": "Export tag"}, 201)["id"].(string)
+	bm := alice.request("POST", "/api/bookmarks", map[string]any{"url": "https://127.0.0.1/export", "title": "Exported bookmark", "tagIds": []string{tag}}, 201)["id"].(string)
+	page := alice.request("POST", "/api/pages", map[string]any{"title": "Exported page", "content": "exported body"}, 201)["id"].(string)
+	col := alice.request("POST", "/api/collections", map[string]any{"name": "Exported collection"}, 201)["id"].(string)
+	alice.request("POST", "/api/collections/"+col+"/items", map[string]any{"bookmarkId": bm}, 201)
+
+	v := alice.request("GET", "/api/export", nil, 200)
+	if v["format"] != "computer-export" || v["version"].(float64) != 1 {
+		t.Fatalf("export envelope: %v", v)
+	}
+	if len(v["bookmarks"].([]any)) != 1 || len(v["pages"].([]any)) != 1 || len(v["tags"].([]any)) != 1 || len(v["collections"].([]any)) != 1 {
+		t.Fatalf("export sections: %v", v)
+	}
+	exPage := v["pages"].([]any)[0].(map[string]any)
+	if exPage["content"] != "exported body" || len(exPage["revisions"].([]any)) == 0 {
+		t.Fatalf("export page content/history: %v", exPage)
+	}
+	exCol := v["collections"].([]any)[0].(map[string]any)
+	if len(exCol["items"].([]any)) != 1 {
+		t.Fatalf("export collection items: %v", exCol)
+	}
+	if _, ok := v["user"].(map[string]any)["id"]; !ok {
+		t.Fatalf("export user identity: %v", v["user"])
+	}
+	if page == "" {
+		t.Fatal("page id missing")
+	}
+}

web/app/(app)/bookmarks/client.tsx

@@ -176,7 +176,7 @@ export function BookmarksClient({ initialSearch = null, initialOpen = null }: {
                     <div className="flex gap-1" onClick={(e: React.MouseEvent) => e.stopPropagation()}>
                       <a href={b.url} target="_blank" rel="noopener noreferrer"><ExternalLink className="h-4 w-4 text-muted-foreground hover:text-primary" /></a>
                       {tab === 'mine' && (
-                        <button onClick={async () => { if (!confirm('Delete?')) return; try { const res = await fetch(`/api/bookmarks/${b.id}`, { method: 'DELETE' }); if (res.ok) { toast.success('Deleted'); load() } else toast.error('Could not delete bookmark') } catch { toast.error('Could not delete bookmark') } }}><Trash2 className="h-4 w-4 text-muted-foreground hover:text-destructive" /></button>
+                        <button onClick={async () => { if (!confirm('Move this bookmark to the trash? It can be restored.')) return; try { const res = await fetch(`/api/bookmarks/${b.id}`, { method: 'DELETE' }); if (res.ok) { toast.success('Moved to trash'); load() } else toast.error('Could not move bookmark to trash') } catch { toast.error('Could not move bookmark to trash') } }}><Trash2 className="h-4 w-4 text-muted-foreground hover:text-destructive" /></button>
                       )}
                     </div>
                   </td>

web/app/(app)/collections/client.tsx

@@ -11,7 +11,7 @@ import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover
 import { Dialog, DialogContent, DialogHeader, DialogTitle } from '@/components/ui/dialog'
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select'
 import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from '@/components/ui/table'
-import { CalendarDays, Columns3, Filter, GripVertical, Kanban, Layers, List, Plus, Table2, Trash2, X } from 'lucide-react'
+import { CalendarDays, Columns3, Filter, GripVertical, Kanban, Layers, List, Plus, Share2, Table2, Trash2, X } from 'lucide-react'
 import { toast } from 'sonner'
 import type { Bookmark } from '@/components/app-shell'
 import { cn } from '@/lib/utils'
@@ -40,9 +40,13 @@ type CollectionItem = {
   propertyValues: Record<string, unknown>; position: number; version: number
   addedAt: string; updatedAt: string; bookmark: Bookmark
 }
+type CollectionShare = { userId: string; name: string | null; email: string | null; createdAt?: string }
 type CollectionSummary = {
   id: string; name: string; description: string | null; icon: string | null
   version: number; createdAt: string; updatedAt: string
+  shared: boolean
+  owner?: { id: string; name: string | null; email: string | null; image: string | null }
+  sharedWith?: CollectionShare[]
   _count: { items: number; properties: number; views: number }
 }
 type CollectionDetail = CollectionSummary & { properties: CollectionProperty[]; views: CollectionView[] }
@@ -95,10 +99,27 @@ function BookmarkCell({ bookmark }: { bookmark: Bookmark }) {
 
 const asText = (v: unknown) => (typeof v === 'string' || typeof v === 'number' ? String(v) : '')
 
+function plainValue(prop: CollectionProperty, value: unknown): string {
+  if (prop.type === 'CHECKBOX') return value === true ? 'Yes' : 'No'
+  if (prop.type === 'SELECT') return prop.config.options?.find((o) => o.id === value)?.label ?? '—'
+  if (prop.type === 'MULTI_SELECT') {
+    if (!Array.isArray(value)) return '—'
+    return value.map((id) => prop.config.options?.find((o) => o.id === id)?.label).filter(Boolean).join(', ') || '—'
+  }
+  if (prop.type === 'DATE' && typeof value === 'string' && value) {
+    if (prop.config.mode === 'date') return value.slice(0, 10)
+    const date = new Date(value)
+    return Number.isNaN(date.getTime()) ? value : date.toLocaleString()
+  }
+  if (value === null || value === undefined || value === '') return '—'
+  return String(value)
+}
+
 // Per-type inline value editor. Saves immediately on commit gestures
 // (change/blur/Enter); failures toast and the prop value re-renders the
-// server state, so a rejected edit never sticks locally.
-function ValueEditor({ prop, value, onSave }: { prop: CollectionProperty; value: unknown; onSave: (v: unknown) => Promise<void> }) {
+// server state, so a rejected edit never sticks locally. Shared collections
+// are read-only: the same cell renders plain text.
+function ValueEditor({ prop, value, onSave, readOnly = false }: { prop: CollectionProperty; value: unknown; onSave: (v: unknown) => Promise<void>; readOnly?: boolean }) {
   const [text, setText] = useState(() => asText(value))
   const [seen, setSeen] = useState(value)
   // Adjusting state when a prop changes: the React-documented render-time
@@ -108,6 +129,7 @@ function ValueEditor({ prop, value, onSave }: { prop: CollectionProperty; value:
     setText(asText(value))
   }
   const [open, setOpen] = useState(false)
+  if (readOnly) return <span className="text-sm text-muted-foreground">{plainValue(prop, value)}</span>
   const commitText = async () => {
     const next = text.trim()
     const current = asText(value)
@@ -220,6 +242,9 @@ export function CollectionsClient() {
   const [fProp, setFProp] = useState('')
   const [fOp, setFOp] = useState('eq')
   const [fValue, setFValue] = useState('')
+  const [shareOpen, setShareOpen] = useState(false)
+  const [shareQuery, setShareQuery] = useState('')
+  const [shareResults, setShareResults] = useState<{ id: string; name: string | null; email: string }[]>([])
 
   const loadCollections = useCallback(async () => {
     try {
@@ -293,6 +318,41 @@ export function CollectionsClient() {
 
   const activeView = detail?.views.find((v) => v.id === viewId) ?? null
   const groupProp = activeView?.groupByPropertyId ? detail?.properties.find((p) => p.id === activeView.groupByPropertyId) : null
+  // Shared collections are explicitly read-only: hiding mutation controls is
+  // the UI half of the server's owner-only mutation gate.
+  const readOnly = detail?.shared === true
+
+  const shareCollection = async (userId: string) => {
+    if (!detail) return
+    const res = await fetch(`/api/collections/${detail.id}/share`, {
+      method: 'POST', headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ userIds: [userId] }),
+    })
+    if (!res.ok) { toast.error('Could not share collection'); return }
+    toast.success('Collection shared')
+    setShareQuery(''); setShareResults([])
+    loadDetail(detail.id); loadCollections()
+  }
+  const unshareCollection = async (userId: string) => {
+    if (!detail) return
+    const res = await fetch(`/api/collections/${detail.id}/share/${userId}`, { method: 'DELETE' })
+    if (!res.ok) { toast.error('Could not revoke collection access'); return }
+    toast.success('Access revoked')
+    loadDetail(detail.id); loadCollections()
+  }
+
+  useEffect(() => {
+    if (!shareOpen) return
+    const q = shareQuery.trim()
+    if (q.length < 2) return
+    const t = setTimeout(async () => {
+      try {
+        const res = await fetch(`/api/users/search?q=${encodeURIComponent(q)}`)
+        if (res.ok) setShareResults(await res.json())
+      } catch { /* transient */ }
+    }, 250)
+    return () => clearTimeout(t)
+  }, [shareOpen, shareQuery])
 
   const createCollection = async () => {
     const name = newName.trim()
@@ -307,7 +367,7 @@ export function CollectionsClient() {
   }
 
   const saveName = async () => {
-    if (!detail) return
+    if (!detail || detail.shared) return
     const name = nameDraft.trim()
     if (!name || name === detail.name) { setNameDraft(detail.name); return }
     const res = await patch(`/api/collections/${detail.id}`, { version: detail.version, name })
@@ -318,7 +378,7 @@ export function CollectionsClient() {
   }
 
   const deleteCollection = async () => {
-    if (!detail || !confirm(`Delete collection "${detail.name}"? Bookmarks are kept.`)) return
+    if (!detail || detail.shared || !confirm(`Move collection "${detail.name}" to the trash? Bookmarks are kept and it can be restored.`)) return
     const res = await fetch(`/api/collections/${detail.id}`, { method: 'DELETE' })
     if (await mutate(res, loadCollections, 'Collection deleted')) {
       setActiveId(null)
@@ -494,9 +554,9 @@ export function CollectionsClient() {
               <TableHead key={p.id} className="min-w-[11rem]">
                 <span className="flex items-center gap-1.5">
                   {p.name}
-                  <button type="button" aria-label={`Delete property ${p.name}`} className="text-muted-foreground opacity-0 transition-opacity hover:text-destructive group-hover:opacity-100" onClick={() => deleteProperty(p)}>
+                  {!readOnly && <button type="button" aria-label={`Delete property ${p.name}`} className="text-muted-foreground opacity-0 transition-opacity hover:text-destructive group-hover:opacity-100" onClick={() => deleteProperty(p)}>
                     <Trash2 className="h-3 w-3" />
-                  </button>
+                  </button>}
                 </span>
               </TableHead>
             ))}
@@ -508,12 +568,12 @@ export function CollectionsClient() {
             <TableRow key={item.id} className="group">
               <TableCell><BookmarkCell bookmark={item.bookmark} /></TableCell>
               {(detail?.properties ?? []).map((p) => (
-                <TableCell key={p.id}><ValueEditor prop={p} value={item.propertyValues?.[p.id]} onSave={(v) => saveValue(item, p.id, v)} /></TableCell>
+                <TableCell key={p.id}><ValueEditor prop={p} value={item.propertyValues?.[p.id]} onSave={(v) => saveValue(item, p.id, v)} readOnly={readOnly} /></TableCell>
               ))}
               <TableCell>
-                <button type="button" aria-label="Remove from collection" className="text-muted-foreground hover:text-destructive" onClick={() => removeItem(item)}>
+                {!readOnly && <button type="button" aria-label="Remove from collection" className="text-muted-foreground hover:text-destructive" onClick={() => removeItem(item)}>
                   <Trash2 className="h-4 w-4" />
-                </button>
+                </button>}
               </TableCell>
             </TableRow>
           ))}
@@ -535,7 +595,7 @@ export function CollectionsClient() {
         <div className="rounded-lg border border-dashed border-border p-8 text-center">
           <Kanban className="mx-auto mb-2 h-8 w-8 text-muted-foreground" />
           <p className="text-sm text-muted-foreground">Board views group by a select property.</p>
-          <div className="mx-auto mt-3 w-56">
+          {!readOnly && <div className="mx-auto mt-3 w-56">
             <Select
               value={NONE}
               onValueChange={(id) => { if (id !== NONE) patchView({ groupByPropertyId: id }) }}
@@ -547,7 +607,7 @@ export function CollectionsClient() {
                 ))}
               </SelectContent>
             </Select>
-          </div>
+          </div>}
         </div>
       )
     }
@@ -602,7 +662,7 @@ export function CollectionsClient() {
                     )}
                   >
                     <div className="flex items-start gap-1">
-                      <span
+                      {!readOnly && <span
                         data-drag-handle
                         draggable
                         onDragStart={(e) => {
@@ -619,25 +679,29 @@ export function CollectionsClient() {
                         aria-label={`Drag ${item.bookmark.title ?? 'bookmark'}`}
                       >
                         <GripVertical className="h-3.5 w-3.5" />
-                      </span>
+                      </span>}
                       <div className="min-w-0 flex-1">
                         <BookmarkCell bookmark={item.bookmark} />
                       </div>
                     </div>
                     <div className="mt-1.5 flex items-center justify-between gap-1">
-                      <Select
-                        value={typeof item.propertyValues?.[groupProp.id] === 'string' ? (item.propertyValues[groupProp.id] as string) : NONE}
-                        onValueChange={(id) => { void moveItemToGroup(item, id === NONE ? null : id) }}
-                      >
-                        <SelectTrigger className="h-7 w-28 text-xs" aria-label={`Move ${item.bookmark.title ?? 'card'}`}><SelectValue /></SelectTrigger>
-                        <SelectContent>
-                          <SelectItem value={NONE}>—</SelectItem>
-                          {options.map((o) => <SelectItem key={o.id} value={o.id}>{o.label}</SelectItem>)}
-                        </SelectContent>
-                      </Select>
-                      <button type="button" aria-label="Remove from collection" className="text-muted-foreground hover:text-destructive" onClick={() => removeItem(item)}>
+                      {readOnly ? (
+                        <span className="text-xs text-muted-foreground">{plainValue(groupProp, item.propertyValues?.[groupProp.id])}</span>
+                      ) : (
+                        <Select
+                          value={typeof item.propertyValues?.[groupProp.id] === 'string' ? (item.propertyValues[groupProp.id] as string) : NONE}
+                          onValueChange={(id) => { void moveItemToGroup(item, id === NONE ? null : id) }}
+                        >
+                          <SelectTrigger className="h-7 w-28 text-xs" aria-label={`Move ${item.bookmark.title ?? 'card'}`}><SelectValue /></SelectTrigger>
+                          <SelectContent>
+                            <SelectItem value={NONE}>—</SelectItem>
+                            {options.map((o) => <SelectItem key={o.id} value={o.id}>{o.label}</SelectItem>)}
+                          </SelectContent>
+                        </Select>
+                      )}
+                      {!readOnly && <button type="button" aria-label="Remove from collection" className="text-muted-foreground hover:text-destructive" onClick={() => removeItem(item)}>
                         <Trash2 className="h-3.5 w-3.5" />
-                      </button>
+                      </button>}
                     </div>
                   </div>
                 ))}
@@ -674,7 +738,10 @@ export function CollectionsClient() {
                 className={cn('flex w-full items-center gap-2 rounded-md px-2 py-1.5 text-left text-sm transition-colors', c.id === activeId ? 'bg-primary/10 font-medium text-primary' : 'text-muted-foreground hover:bg-muted hover:text-foreground')}
               >
                 <Layers className="h-3.5 w-3.5 shrink-0" />
-                <span className="min-w-0 flex-1 truncate">{c.name}</span>
+                <span className="min-w-0 flex-1 truncate">
+                  {c.name}
+                  {c.shared && <span className="ml-1 text-[10px] uppercase tracking-wide text-muted-foreground">shared</span>}
+                </span>
                 <span className="shrink-0 text-xs text-muted-foreground">{c._count.items}</span>
               </button>
             ))}
@@ -699,13 +766,25 @@ export function CollectionsClient() {
           ) : (
             <>
               <div className="mb-4 flex flex-wrap items-center gap-2">
-                <Input value={nameDraft} onChange={(e) => setNameDraft(e.target.value)} onBlur={saveName} onKeyDown={(e) => { if (e.key === 'Enter') (e.target as HTMLInputElement).blur() }} aria-label="Collection name" className="w-72 bg-transparent font-display text-2xl font-bold tracking-tight" />
+                {readOnly ? (
+                  <span className="w-72 truncate font-display text-2xl font-bold tracking-tight">{detail.name}</span>
+                ) : (
+                  <Input value={nameDraft} onChange={(e) => setNameDraft(e.target.value)} onBlur={saveName} onKeyDown={(e) => { if (e.key === 'Enter') (e.target as HTMLInputElement).blur() }} aria-label="Collection name" className="w-72 bg-transparent font-display text-2xl font-bold tracking-tight" />
+                )}
                 <span className="text-xs text-muted-foreground">{detail._count?.items ?? 0} item{(detail._count?.items ?? 0) === 1 ? '' : 's'}</span>
-                <div className="ml-auto flex items-center gap-1.5">
-                  <Button size="sm" variant="outline" onClick={() => setAddOpen(true)}><Plus className="mr-1 h-4 w-4" />Add bookmarks</Button>
-                  <Button size="sm" variant="outline" onClick={() => setPropOpen(true)}><Plus className="mr-1 h-4 w-4" />Property</Button>
-                  <Button size="sm" variant="ghost" onClick={deleteCollection} aria-label="Delete collection" title="Delete collection"><Trash2 className="h-4 w-4 text-destructive" /></Button>
-                </div>
+                {readOnly ? (
+                  <Badge variant="secondary" className="gap-1">
+                    <Share2 className="h-3 w-3" />
+                    Shared by {detail.owner?.name || detail.owner?.email || 'another user'} · read-only
+                  </Badge>
+                ) : (
+                  <div className="ml-auto flex items-center gap-1.5">
+                    <Button size="sm" variant="outline" onClick={() => setAddOpen(true)}><Plus className="mr-1 h-4 w-4" />Add bookmarks</Button>
+                    <Button size="sm" variant="outline" onClick={() => setPropOpen(true)}><Plus className="mr-1 h-4 w-4" />Property</Button>
+                    <Button size="sm" variant="outline" onClick={() => { setShareOpen(true); setShareResults([]); setShareQuery('') }}><Share2 className="mr-1 h-4 w-4" />Share</Button>
+                    <Button size="sm" variant="ghost" onClick={deleteCollection} aria-label="Move collection to trash" title="Move collection to trash"><Trash2 className="h-4 w-4 text-destructive" /></Button>
+                  </div>
+                )}
               </div>
 
               {/* View tabs */}
@@ -722,8 +801,8 @@ export function CollectionsClient() {
                     </button>
                   )
                 })}
-                <Button size="sm" variant="ghost" className="h-7 px-2" onClick={() => setViewOpen(true)} aria-label="Add view"><Plus className="h-4 w-4" /></Button>
-                {activeView && (
+                {!readOnly && <Button size="sm" variant="ghost" className="h-7 px-2" onClick={() => setViewOpen(true)} aria-label="Add view"><Plus className="h-4 w-4" /></Button>}
+                {activeView && !readOnly && (
                   <div className="ml-auto flex items-center gap-1.5">
                     <Popover open={filterOpen} onOpenChange={(o) => { setFilterOpen(o); if (o) { setFProp(detail.properties[0]?.id ?? ''); setFOp(FILTER_OPS[detail.properties[0]?.type ?? 'TEXT']?.[0] ?? 'eq') } }}>
                       <PopoverTrigger asChild>
@@ -774,7 +853,7 @@ export function CollectionsClient() {
                   {filterClauses.map((c, i) => (
                     <Badge key={i} variant="secondary" className="gap-1">
                       {clauseLabel(c)}
-                      <button type="button" aria-label="Remove filter" onClick={() => setClause(filterClauses.filter((_, j) => j !== i))}><X className="h-3 w-3" /></button>
+                      {!readOnly && <button type="button" aria-label="Remove filter" onClick={() => setClause(filterClauses.filter((_, j) => j !== i))}><X className="h-3 w-3" /></button>}
                     </Badge>
                   ))}
                 </div>
@@ -878,6 +957,48 @@ export function CollectionsClient() {
           </div>
         </DialogContent>
       </Dialog>
+
+      {/* Share dialog */}
+      <Dialog open={shareOpen} onOpenChange={(o) => { setShareOpen(o); if (!o) { setShareQuery(''); setShareResults([]) } }}>
+        <DialogContent className="max-w-lg">
+          <DialogHeader><DialogTitle>Share collection</DialogTitle></DialogHeader>
+          <p className="text-xs text-muted-foreground">
+            Recipients get read-only access to this collection and the links you own inside it. Links you can
+            only see through someone else&apos;s share are omitted, so sharing never passes a third-party grant on.
+            They receive the same trimmed link view as other shared bookmarks; contacts, alerts and mailbox
+            settings stay private. Revoking access takes effect immediately.
+          </p>
+          {detail && (
+            <div className="space-y-1">
+              {(detail.sharedWith ?? []).map((s) => (
+                <div key={s.userId} className="flex items-center gap-2 rounded-md border px-2 py-1.5 text-sm">
+                  <span className="min-w-0 flex-1 truncate">{s.name || s.email || s.userId}</span>
+                  <Button size="sm" variant="ghost" onClick={() => void unshareCollection(s.userId)}>Revoke</Button>
+                </div>
+              ))}
+              {(detail.sharedWith?.length ?? 0) === 0 && <p className="py-2 text-xs text-muted-foreground">Not shared with anyone yet.</p>}
+            </div>
+          )}
+          <Input autoFocus value={shareQuery} onChange={(e) => setShareQuery(e.target.value)} placeholder="Search people by name or email" aria-label="Search people to share with" />
+          <div className="max-h-56 space-y-1 overflow-y-auto">
+            {shareResults.map((u) => {
+              const already = detail?.sharedWith?.some((s) => s.userId === u.id)
+              return (
+                <div key={u.id} className="flex items-center gap-2 rounded-md border px-2 py-1.5 text-sm">
+                  <div className="min-w-0 flex-1">
+                    <p className="truncate">{u.name || u.email}</p>
+                    {u.name && <p className="truncate text-xs text-muted-foreground">{u.email}</p>}
+                  </div>
+                  <Button size="sm" variant="outline" disabled={already} onClick={() => void shareCollection(u.id)}>
+                    {already ? 'Shared' : 'Share'}
+                  </Button>
+                </div>
+              )
+            })}
+            {shareQuery.trim().length >= 2 && shareResults.length === 0 && <p className="py-4 text-center text-xs text-muted-foreground">No matching people</p>}
+          </div>
+        </DialogContent>
+      </Dialog>
     </div>
   )
 }

web/app/(app)/pages/client.tsx

@@ -8,12 +8,13 @@ import remarkGfm from 'remark-gfm'
 import { toast } from 'sonner'
 import {
   ChevronLeft, ChevronRight, Code, CornerUpLeft, Download, Eye, FileText, GripVertical,
-  Heading1, Heading2, Heading3, Layers, Link2, List, ListOrdered, ListTodo, Minus, Pencil, Pin, PinOff,
-  Plus, Quote, Search, Trash2, Type, X,
+  Heading1, Heading2, Heading3, History, Layers, Link2, List, ListOrdered, ListTodo, Minus, Pencil,
+  Pin, PinOff, Plus, Quote, RotateCcw, Search, Trash2, Type, X,
 } from 'lucide-react'
 import { Button } from '@/components/ui/button'
 import { Input } from '@/components/ui/input'
 import { Textarea } from '@/components/ui/textarea'
+import { Dialog, DialogContent, DialogHeader, DialogTitle } from '@/components/ui/dialog'
 import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover'
 import { cn } from '@/lib/utils'
 import { PageAutosave, PageConflictError, type PageSaveState } from '@/lib/page-autosave'
@@ -65,6 +66,8 @@ type PageDetail = PageSummary & {
   links: { id: string; title: string }[]
   embeds: PageEmbed[]
 }
+type PageRevisionSummary = { id: string; version: number; title: string; createdAt: string; length: number }
+type PageRevisionDetail = PageRevisionSummary & { content: string; icon: string | null }
 
 const notify = notifyPagesChanged
 const host = (u: string) => { try { return new URL(u).hostname.replace(/^www\./, '') } catch { return u } }
@@ -192,6 +195,10 @@ export function PagesClient({ initialId }: { initialId: string | null }) {
   const [pageLinkQuery, setPageLinkQuery] = useState('')
   const [embedOpen, setEmbedOpen] = useState(false)
   const [collections, setCollections] = useState<{ id: string; name: string; icon: string | null; views?: { id: string; name: string }[] }[]>([])
+  const [historyOpen, setHistoryOpen] = useState(false)
+  const [revisions, setRevisions] = useState<PageRevisionSummary[]>([])
+  const [revision, setRevision] = useState<PageRevisionDetail | null>(null)
+  const [historyBusy, setHistoryBusy] = useState<string | null>(null)
   const [slash, setSlash] = useState<{ query: string; start: number } | null>(null)
   const [slashIndex, setSlashIndex] = useState(0)
   const [tabDrop, setTabDrop] = useState<{ id: string; after: boolean } | null>(null)
@@ -388,6 +395,60 @@ export function PagesClient({ initialId }: { initialId: string | null }) {
     }
   }
 
+  const openHistory = async () => {
+    if (!page) return
+    setHistoryOpen(true)
+    setRevision(null)
+    try {
+      const res = await fetch(`/api/pages/${page.id}/revisions`, { cache: 'no-store' })
+      setRevisions(res.ok ? await res.json() : [])
+      if (!res.ok) toast.error('Could not load page history')
+    } catch { toast.error('Could not load page history') }
+  }
+  const viewRevision = async (id: string) => {
+    if (!page) return
+    setHistoryBusy(id)
+    try {
+      const res = await fetch(`/api/pages/${page.id}/revisions/${id}`, { cache: 'no-store' })
+      if (res.ok) setRevision(await res.json())
+      else toast.error('Could not load this version')
+    } catch { toast.error('Could not load this version') }
+    finally { setHistoryBusy(null) }
+  }
+  const restoreRevision = async (rev: PageRevisionSummary) => {
+    if (!page) return
+    if (!confirm(`Restore version ${rev.version}? The current content is kept in history.`)) return
+    setHistoryBusy(rev.id)
+    try {
+      if (!await autosave.flush(page.id)) { toast.error('Resolve the unsaved draft before restoring history'); return }
+      const latest = await fetch(`/api/pages/${page.id}`, { cache: 'no-store' })
+      if (!latest.ok) { toast.error('Could not reload the page'); return }
+      const current: PageDetail = await latest.json()
+      const res = await fetch(`/api/pages/${page.id}/revisions/${rev.id}/restore`, {
+        method: 'POST', headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ version: current.version }),
+      })
+      if (res.status === 409) {
+        toast.error('The page changed elsewhere. Reload it before restoring history.')
+        await loadPage(page.id)
+        return
+      }
+      if (!res.ok) { toast.error((await res.json().catch(() => null))?.error ?? 'Could not restore this version'); return }
+      const restored: PageDetail = await res.json()
+      autosave.discard(page.id)
+      autosave.setVersion(page.id, restored.version)
+      setPage(restored)
+      setTitle(restored.title)
+      setContent(restored.content)
+      setMode('preview')
+      notifyActivePage(restored.title)
+      setHistoryOpen(false)
+      toast.success(`Restored version ${rev.version} as version ${restored.version}`)
+      await loadPages(); notify()
+    } catch { toast.error('Could not restore this version') }
+    finally { setHistoryBusy(null) }
+  }
+
   // Show the block menu only while the caret sits on a bare "/token" line.
   const updateSlash = (text: string, caret: number) => {
     const lineStart = text.lastIndexOf('\n', caret - 1) + 1
@@ -504,7 +565,7 @@ export function PagesClient({ initialId }: { initialId: string | null }) {
   }
 
   const remove = async () => {
-    if (!page || !confirm(`Delete page "${page.title}"? Bookmarks are kept.`)) return
+    if (!page || !confirm(`Move page "${page.title}" to the trash? Bookmarks are kept and it can be restored.`)) return
     if (!await autosave.flush(page.id)) return
     const res = await fetch(`/api/pages/${page.id}`, { method: 'DELETE' })
     if (!res.ok) { toast.error('Could not delete page'); return }
@@ -694,7 +755,8 @@ export function PagesClient({ initialId }: { initialId: string | null }) {
             <Button variant="ghost" size="icon-sm" title="Move tab left" onClick={() => move(-1)}><ChevronLeft className="h-4 w-4" /></Button>
             <Button variant="ghost" size="icon-sm" title="Move tab right" onClick={() => move(1)}><ChevronRight className="h-4 w-4" /></Button>
             <Button variant="ghost" size="icon-sm" title="Download .md" onClick={download}><Download className="h-4 w-4" /></Button>
-            <Button variant="ghost" size="icon-sm" title="Delete page" onClick={remove}><Trash2 className="h-4 w-4 text-destructive" /></Button>
+            <Button variant="ghost" size="icon-sm" title="Version history" onClick={() => void openHistory()}><History className="h-4 w-4" /></Button>
+            <Button variant="ghost" size="icon-sm" title="Move to trash" onClick={remove}><Trash2 className="h-4 w-4 text-destructive" /></Button>
           </div>
 
           <div className="mb-4 flex flex-wrap items-center gap-2 text-sm">
@@ -934,6 +996,49 @@ export function PagesClient({ initialId }: { initialId: string | null }) {
           )}
         </div>
       )}
+
+      <Dialog open={historyOpen} onOpenChange={(open) => { setHistoryOpen(open); if (!open) setRevision(null) }}>
+        <DialogContent className="max-w-3xl">
+          <DialogHeader><DialogTitle>Version history</DialogTitle></DialogHeader>
+          <p className="text-xs text-muted-foreground">
+            Every saved content version is kept. Restoring writes a new version, so nothing in history is ever rewritten.
+          </p>
+          <div className="grid gap-3 md:grid-cols-[15rem_1fr]">
+            <div className="max-h-[24rem] space-y-1 overflow-y-auto rounded-md border p-1">
+              {revisions.map((rev) => (
+                <div key={rev.id} className={cn('rounded-md px-2 py-1.5', revision?.id === rev.id ? 'bg-accent' : 'hover:bg-muted')}>
+                  <button type="button" className="flex w-full items-center justify-between gap-2 text-left" onClick={() => void viewRevision(rev.id)}>
+                    <span className="min-w-0">
+                      <span className="block truncate text-sm font-medium">Version {rev.version}</span>
+                      <span className="block text-xs text-muted-foreground">{new Date(rev.createdAt).toLocaleString()}</span>
+                    </span>
+                    {revisions[0]?.id === rev.id && <span className="shrink-0 text-[10px] uppercase tracking-wide text-muted-foreground">Current</span>}
+                  </button>
+                  <button
+                    type="button"
+                    disabled={historyBusy === rev.id}
+                    onClick={() => void restoreRevision(rev)}
+                    className="mt-1 flex items-center gap-1 text-xs text-primary hover:underline disabled:opacity-50"
+                  >
+                    <RotateCcw className="h-3 w-3" /> Restore
+                  </button>
+                </div>
+              ))}
+              {revisions.length === 0 && <p className="px-2 py-6 text-center text-xs text-muted-foreground">No saved versions yet.</p>}
+            </div>
+            <div className="max-h-[24rem] overflow-y-auto rounded-md border bg-muted/20 p-3">
+              {revision ? (
+                <>
+                  <p className="mb-2 text-sm font-medium">{revision.title}</p>
+                  <pre className="whitespace-pre-wrap break-words font-mono text-xs text-muted-foreground">{revision.content || '(empty page)'}</pre>
+                </>
+              ) : (
+                <p className="py-10 text-center text-sm text-muted-foreground">Select a version to preview it.</p>
+              )}
+            </div>
+          </div>
+        </DialogContent>
+      </Dialog>
     </div>
   )
 }

web/app/(app)/trash/client.tsx

@@ -0,0 +1,120 @@
+'use client'
+
+import { useCallback, useEffect, useState } from 'react'
+import { Download, FileText, Layers, Link2, RotateCcw, Trash2 } from 'lucide-react'
+import { toast } from 'sonner'
+import { Button } from '@/components/ui/button'
+import { Badge } from '@/components/ui/badge'
+import { notifyPagesChanged } from '@/lib/pages'
+
+type TrashEntry = { id: string; type: 'bookmark' | 'page' | 'collection'; originalId: string; title: string; deletedAt: string }
+
+const TYPE_ICON = { bookmark: Link2, page: FileText, collection: Layers } as const
+
+export function TrashClient() {
+  const [entries, setEntries] = useState<TrashEntry[]>([])
+  const [busy, setBusy] = useState<string | null>(null)
+  const [exporting, setExporting] = useState(false)
+
+  const load = useCallback(async () => {
+    try {
+      const res = await fetch('/api/trash', { cache: 'no-store' })
+      if (!res.ok) { toast.error('Could not load the trash'); return }
+      setEntries(await res.json())
+    } catch { toast.error('Could not load the trash') }
+  }, [])
+
+  useEffect(() => {
+    const timer = setTimeout(() => { void load() }, 0)
+    return () => clearTimeout(timer)
+  }, [load])
+
+  const restore = async (entry: TrashEntry) => {
+    setBusy(entry.id)
+    try {
+      const res = await fetch(`/api/trash/${entry.id}/restore`, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: '{}' })
+      if (!res.ok) { toast.error((await res.json().catch(() => null))?.error ?? 'Could not restore'); return }
+      toast.success(`Restored “${entry.title}”`)
+      if (entry.type === 'page') notifyPagesChanged()
+      await load()
+    } catch { toast.error('Could not restore') }
+    finally { setBusy(null) }
+  }
+
+  const purge = async (entry: TrashEntry) => {
+    if (!confirm(`Delete “${entry.title}” permanently? This cannot be undone.`)) return
+    setBusy(entry.id)
+    try {
+      const res = await fetch(`/api/trash/${entry.id}`, { method: 'DELETE' })
+      if (!res.ok) { toast.error('Could not delete permanently'); return }
+      toast.success('Deleted permanently')
+      await load()
+    } catch { toast.error('Could not delete permanently') }
+    finally { setBusy(null) }
+  }
+
+  const exportData = async () => {
+    setExporting(true)
+    try {
+      const res = await fetch('/api/export')
+      if (!res.ok) { toast.error('Could not export your data'); return }
+      const blob = await res.blob()
+      const url = URL.createObjectURL(blob)
+      const a = document.createElement('a')
+      a.href = url
+      a.download = `computer-export-${new Date().toISOString().slice(0, 10)}.json`
+      document.body.appendChild(a); a.click(); a.remove()
+      URL.revokeObjectURL(url)
+      toast.success('Export downloaded')
+    } catch { toast.error('Could not export your data') }
+    finally { setExporting(false) }
+  }
+
+  return (
+    <div className="mx-auto w-full max-w-3xl px-6 py-8">
+      <div className="mb-6 flex flex-wrap items-center gap-2">
+        <div className="min-w-0 flex-1">
+          <h1 className="font-display text-2xl font-bold tracking-tight">Trash</h1>
+          <p className="mt-1 text-sm text-muted-foreground">
+            Deleted bookmarks, pages and collections stay recoverable here. Restoring brings back content and
+            owner-scoped links, but never a share or public link that was revoked in the meantime.
+          </p>
+        </div>
+        <Button variant="outline" onClick={() => void exportData()} disabled={exporting}>
+          <Download className="mr-1 h-4 w-4" />{exporting ? 'Exporting…' : 'Export all data'}
+        </Button>
+      </div>
+
+      {entries.length === 0 ? (
+        <div className="rounded-lg border border-dashed p-12 text-center">
+          <Trash2 className="mx-auto mb-2 h-8 w-8 text-muted-foreground" />
+          <p className="text-sm text-muted-foreground">The trash is empty.</p>
+        </div>
+      ) : (
+        <div className="space-y-2">
+          {entries.map((entry) => {
+            const Icon = TYPE_ICON[entry.type]
+            return (
+              <div key={entry.id} className="flex flex-wrap items-center gap-3 rounded-lg border bg-card px-3 py-2.5">
+                <Icon className="h-4 w-4 shrink-0 text-muted-foreground" />
+                <div className="min-w-0 flex-1">
+                  <p className="truncate text-sm font-medium">{entry.title}</p>
+                  <p className="text-xs text-muted-foreground">
+                    {new Date(entry.deletedAt).toLocaleString()}
+                  </p>
+                </div>
+                <Badge variant="secondary" className="capitalize">{entry.type}</Badge>
+                <Button size="sm" variant="outline" disabled={busy === entry.id} onClick={() => void restore(entry)}>
+                  <RotateCcw className="mr-1 h-3.5 w-3.5" />Restore
+                </Button>
+                <Button size="sm" variant="ghost" disabled={busy === entry.id} onClick={() => void purge(entry)} aria-label={`Delete ${entry.title} permanently`}>
+                  <Trash2 className="h-3.5 w-3.5 text-destructive" />
+                </Button>
+              </div>
+            )
+          })}
+        </div>
+      )}
+    </div>
+  )
+}

web/app/(app)/trash/page.tsx

@@ -0,0 +1,7 @@
+import { TrashClient } from './client'
+
+export const dynamic = 'force-dynamic'
+
+export default function TrashPage() {
+  return <TrashClient />
+}

web/components/bookmark-detail-sheet.tsx

@@ -141,10 +141,10 @@ export function BookmarkDetailSheet({ bookmark, onClose, onUpdate }: Props) {
   }, [bookmark, notes, title, url, description, tagIds, columnId, contactId, kanban, dueDate, alertAt, isPublic, imapEnabled, imapQuery, onUpdate])
 
   const handleDelete = useCallback(async () => {
-    if (!bookmark || !confirm('Delete this bookmark?')) return
+    if (!bookmark || !confirm('Move this bookmark to the trash? It can be restored.')) return
     const response = await fetch(`/api/bookmarks/${bookmark.id}`, { method: 'DELETE' })
-    if (!response.ok) { toast.error('Could not delete bookmark'); return }
-    toast.success('Bookmark deleted')
+    if (!response.ok) { toast.error('Could not move bookmark to trash'); return }
+    toast.success('Bookmark moved to trash')
     onClose()
     onUpdate()
   }, [bookmark, onClose, onUpdate])

web/components/sidebar.tsx

@@ -26,6 +26,7 @@ const viewItems = [
   { href: '/kanban', label: 'Kanban', icon: Kanban },
   { href: '/collections', label: 'Collections', icon: Layers },
   { href: '/contacts', label: 'Contacts', icon: Users },
+  { href: '/trash', label: 'Trash', icon: Trash2 },
 ]
 
 // Section collapse state persists per browser. useSyncExternalStore keeps it
@@ -205,7 +206,7 @@ function SidebarNav({ open, pathname, isAdmin = false }: { open: boolean; pathna
   }
 
   const removePage = async (p: PageSummary) => {
-    if (!confirm(`Delete page "${p.title}"? Bookmarks are kept.`)) return
+    if (!confirm(`Move page "${p.title}" to the trash? Bookmarks are kept and it can be restored.`)) return
     try {
       const res = await fetch(`/api/pages/${p.id}`, { method: 'DELETE' })
       if (!res.ok) { toast.error('Could not delete page'); return }

web/computer_porting_guide.md

@@ -96,6 +96,12 @@ Composite PK (`sourcePageId`, `targetPageId`), `createdAt`; both Cascade, with a
 ### 2.13c `PageEmbed` (live collection view inside a page)
 Composite PK (`pageId`, `collectionId`), `viewId?` → CollectionView (SetNull), `position` int, `createdAt`; page and collection Cascade. Rebuilt from `{{collection:<id>|view=<viewId>}}` on every content save; only owned collections are stored. Item reads still go through the collection endpoint, so an embed displays, never publishes.
 
+### 2.13d `PageRevision` (server-side page history)
+`id`, `pageId` → Page (Cascade), `version` int, `title`, `content`, `icon?`, `createdAt`; unique (`pageId`, `version`). Every committed content version is snapshotted. Restoring a revision copies it into the live page as a **new** version and records that restore.
+
+### 2.13e `Trash` (recoverable deletions)
+`id`, `ownerId` → User (Cascade), `type` (`bookmark`/`page`/`collection`), `originalId`, `data` jsonb snapshot, `deletedAt`; unique (`type`, `originalId`). Snapshots restore intrinsic content and owner-scoped links, but never access grants (public flags, bookmark/tag/collection shares).
+
 ### 2.14 `SignalSource` (a watcher attached to a bookmark)
 `id`, `type` (e.g. `email`), `config` (JSON, default `{}`), `enabled` (default true), `lastCheckedAt?`, `lastStatus?`, `bookmarkId` → Bookmark (Cascade), `ownerId` → User (Cascade).