feat: large polish pass — UX fixes, per-chat scope, restore/backup, action events

Backend
- Per-chat album scope for Immich commands (search/latest/memory/...): new
  allowed_album_ids on CommandTrackerListener, threaded listener/page kwargs
  through ProviderCommandHandler.handle; PATCH listener-scope endpoint.
- /search and /find accept a trailing page number; Immich client search_smart
  / search_metadata take a page param.
- Immich person-asset lookup switched from removed GET /api/people/{id}/assets
  to POST /api/search/metadata with personIds (fixes /person command and
  auto_organize rules silently returning zero candidates on Immich 1.106+).
- Auto_organize rule now sets the target album's thumbnail to the first added
  image when missing (falls back to any asset type); failures do not fail the
  rule. add_assets_to_album surfaces the Immich error body on non-2xx.
- EventLog.user_id / action_id / action_name columns with defensive migration
  + backfill. Status query filters by user_id directly; Immich/webhook paths
  emit user_id explicitly. action_runner writes an action_success/partial/
  failed event on each non-dry-run.
- Dashboard DELETE /api/status/events (scoped to user_id) + rendering live
  tracker/provider/action names via FK join with snapshot fallback.
- PATCH /api/users/{id} for username/role change with last-admin guard.
- Deletion protection returns structured {message, entity, blocked_by}
  (ApiError carries .blockedBy; frontend opens BlockedByModal).
- Backup prepare-restore → AppSetting markers + atomic write of
  pending_restore.json; lifespan hook applies on next startup and archives
  under data/applied_restores/. apply-restart sends SIGTERM so the lifespan
  shutdown runs; NOTIFY_BRIDGE_SUPERVISED env override gates the button.
  Manual POST /api/backup/files (same format as scheduled).
- New periodic-summary test path reuses shared collect_scheduled_assets
  (limit=0) so test and future production code go through one primitive.
- Per-receiver locale for Telegram test messages (resolves
  TelegramChat.language_override per chat instead of applying the first
  receiver's locale to everyone).
- Bounded concurrency (semaphores) in NotificationDispatcher._preload_asset_data
  and _refresh_telegram_chat_titles; chat title sweep extended to 24h since
  save_chat_from_webhook covers active chats opportunistically.
- Telegram poller detects the \"webhook is active\" 409 and auto-calls
  deleteWebhook for bots whose DB update_mode is polling (throttled per bot).
- TelegramClient.get_chat added (CLAUDE.md rule 6); set_album_thumbnail added.
- Seeds: rename \"Default Commands\" → \"Default Immich Commands\";
  track_assets_removed default False.

Frontend
- Global provider selector visible when there is only one provider.
- Clear-events button + i18n + ConfirmModal on the dashboard; new icons/
  labels/filters/colors for action_success / action_partial / action_failed.
- Auto-select first available tracking/template/command/config + bot on
  create forms (trackers, command-trackers, targets, template/command
  configs).
- Telegram target disable_url_preview defaults to true.
- BlockedByModal wired into 8 deletion flows; fetchAuth helper for
  multipart/binary calls (reuses api()'s refresh + ApiError mapping).
- Immich tracker 'Checking links' parallelised (concurrency cap 6).
- Backup page: pending-restore banner + Apply-now / Apply-later modal,
  restarting overlay polling /api/health, manual 'Create backup' button.
- Command-trackers listener row gets an 'Edit album scope' modal with
  inherit/explicit multiselect.
- Users page: Edit user modal (username + role).
- parseDate helper for consistent UTC date rendering.

Migrations / schema
- event_log: + user_id, action_id, action_name (+ backfill user_id from
  notification_tracker).
- command_tracker_listener: + allowed_album_ids.

frontend/src/routes/+layout.svelte

@@ -384,7 +384,7 @@
 			</div>
 
 			<!-- Global provider filter -->
-			{#if allProviders.length > 1}
+			{#if allProviders.length >= 1}
 				<div class="{collapsed ? 'px-2 py-1' : 'px-3 py-1.5'}" style="border-bottom: 1px solid var(--color-border);">
 					{#if collapsed}
 						<button onclick={() => {
@@ -564,7 +564,7 @@
 				onclick={() => mobileMoreOpen = false} role="presentation"></div>
 			<div class="mobile-more-panel" style="position: fixed; bottom: 3.25rem; left: 0; right: 0; z-index: 50; background: var(--color-sidebar); border-top: 1px solid var(--color-border); border-radius: 1rem 1rem 0 0; padding: 1rem; max-height: 60vh; overflow-y: auto;"
 				transition:slide={{ duration: 200, easing: cubicOut }}>
-				{#if allProviders.length > 1}
+				{#if allProviders.length >= 1}
 					<div class="mb-3 pb-3" style="border-bottom: 1px solid var(--color-border);">
 						<IconGridSelect items={providerFilterItems} bind:value={providerFilterValue} columns={Math.min(providerFilterItems.length, 4)} compact />
 					</div>