Offer to send the log to us when an install or update fails

When update or install.sh fails and there's a terminal, ask whether to
send its log to the CoreDesktop team, with the option of reading exactly
what would be sent first. Nothing is sent without a yes, and nothing is
asked without a terminal. The new report command sends a log later
(report, report FILE) or shows what would be sent (report --view).

Before sending, the log is cleaned of terminal codes, and the home
folder, user name, host name, email addresses, IPv4 addresses and
Tailscale names are replaced. CoreDesktop's version, the kernel's, the
failed steps and sibling versions go along with it. The request format
the receiver on federated.sh implements is described at the top of
report.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -185,7 +185,7 @@ Besides installing software, CoreDesktop changes these settings. They're listed
 - **Services turned on**: Avahi, Bluetooth, CUPS (printing), fwupd, GDM, NetworkManager, reflector (weekly), sshd, Docker, Tailscale, ufw and systemd-oomd. Your user is added to the docker group.
 - **Snapper** (btrfs only): a config for / in /etc/snapper/configs/root.
 - **NVIDIA** (only if it installs the driver): /etc/mkinitcpio.conf.d/nvidia.conf and NVIDIA's suspend services.
-- **Your home folder**: lines in ~/.bashrc (CoreDesktop's shell setup, ~/.local/bin on PATH, the Bitwarden SSH agent), the commands in ~/.local/bin (update, refresh, sibling, version, configure, audit), GNOME extensions and their settings, Claude Code's ~/.claude/settings.json if you had none, a user timer that checks for updates, and a user service that pauses your Core's email if its password stops working (see Configure).
+- **Your home folder**: lines in ~/.bashrc (CoreDesktop's shell setup, ~/.local/bin on PATH, the Bitwarden SSH agent), the commands in ~/.local/bin (update, refresh, sibling, version, configure, audit, report), GNOME extensions and their settings, Claude Code's ~/.claude/settings.json if you had none, a user timer that checks for updates, and a user service that pauses your Core's email if its password stops working (see Configure).
 - **configure** adds more, only for what you set up: your Nextcloud files mount and network storage in /etc/fstab (SMB passwords in /etc/coredesktop/smb, SFTP mounts as user services named coredesktop-sftp-*), printers in CUPS, GNOME Online Accounts, passwords in your GNOME keyring, and the backup timer.
 
 ## Keep your System Up-to-date
@@ -212,6 +212,8 @@ If a step fails, the other steps still run, and the failed ones are listed at th
 
 Each run's full output is saved in ~/.local/state/coredesktop/logs/, so you can read what went wrong after the terminal is gone. `update` keeps the logs of the last 10 updates and the last 3 installs or refreshes.
 
+If an install or update fails, it offers to send its log to the CoreDesktop team so we can find and fix the problem. Nothing is sent unless you say yes, and you can read exactly what would be sent first: your user name, host name, home folder, email addresses, IP addresses and Tailscale names are taken out. Along with the log go CoreDesktop's version, the kernel's, the names of the steps that failed and your sibling projects' versions. You get a report ID to mention if you contact us. To send a log later, run `report` (the newest log) or `report <file>`; `report --view` shows what would be sent without sending anything.
+
 It is a good idea to reboot after an update especially if you see you have a new Linux kernel installed (and that happens frequently enough for Arch).
 
 Note: sometimes, for whatever reason, the update barfs. Take a look at [https://archlinux.org](https://archlinux.org) in the "Latest News" section for fixes.
@@ -357,7 +359,7 @@ Then remove CoreDesktop's own files:
 ```
 systemctl --user disable --now coredesktop-update-check.timer coredesktop-backup.timer coredesktop-email-watch.service
 rm -f ~/.config/systemd/user/coredesktop-*
-rm -f ~/.local/bin/{update,refresh,sibling,version,configure,audit}
+rm -f ~/.local/bin/{update,refresh,sibling,version,configure,audit,report}
 rm -rf ~/.local/share/coredesktop ~/.local/share/siblings ~/.local/state/coredesktop ~/.config/coredesktop
 ```