initial commit on Federted servers

db/migrations/005_contact_source.sql

@@ -0,0 +1,8 @@
+-- 005_contact_source.sql — CardDAV provenance for deletion reconciliation
+-- (review CR-07). Sync mirrors the configured address book, scoped by this
+-- column: only contacts previously imported from the SAME source URL are
+-- candidates for remote-deletion removal; manually created contacts (NULL)
+-- and other address books' imports are never touched. Existing rows keep
+-- NULL and are adopted (stamped with the source) the next time the server
+-- returns them.
+ALTER TABLE "Contact" ADD COLUMN IF NOT EXISTS source text;