packaging/iso: uninstall safety, fail-closed AUR updates, no sshd on live ISO

- tanin-greet.install: post_remove restores the previous greetd config —
  removing the package no longer leaves greetd pointing at a dead binary
- aur-autoupdate: skip packages when the AUR RPC is unreachable instead of
  building blind (fail closed)
- build-tanin-repo: per-package makepkg logs instead of >/dev/null
- live ISO: drop sshd.service enablement (root has an empty password on the
  live medium); encoded in bootstrap-profile.sh so it survives re-bootstrap
- gtklock config: de-personalize hardcoded /home/karim path, mark as
  not-yet-packaged reference
- tanin-desktop PKGBUILD: correct stale AUR-vs-extra comments (gtklock,
  awww, cliphist are in extra), document the eww-git provides=eww contract
- docs/distribution.md: mark SigLevel TrustAll as temporary/insecure, add
  repo-signing TODO (repo-add -s, SigLevel Required), tick done roadmap items
- tanin-calendar + niri-config.kdl: pending session work

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packaging/aur-autoupdate.sh

@@ -67,7 +67,10 @@ should_build() {
   local p="$1"
   [[ "$p" == *-git ]] && return 0
   local rpc; rpc="$(aur_version "$p")"
-  [ -z "$rpc" ] && return 0                      # RPC down → build to be safe
+  if [ -z "$rpc" ]; then                         # RPC unreachable → fail closed
+    log "WARNING: AUR RPC unreachable for $p — skipping (won't build blind)"
+    return 1
+  fi
   local last; last="$(cat "$CACHE/$p.ver" 2>/dev/null || echo)"
   [ "$rpc" != "$last" ]
 }