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/targets/+page.svelte

@@ -1,7 +1,8 @@
 <script lang="ts">
 	import { onMount, tick } from 'svelte';
 	import { page } from '$app/state';
-	import { api } from '$lib/api';
+	import { api, getBlockedBy, type BlockedByDetail } from '$lib/api';
+	import BlockedByModal from '$lib/components/BlockedByModal.svelte';
 	import { t, getLocale } from '$lib/i18n';
 	import { targetsCache, telegramBotsCache, emailBotsCache, matrixBotsCache } from '$lib/stores/caches.svelte';
 	import PageHeader from '$lib/components/PageHeader.svelte';
@@ -114,7 +115,7 @@
 	const defaultForm = () => ({
 		name: '', icon: '', bot_id: 0, bot_token: '',
 		max_media_to_send: 50, max_media_per_group: 10, media_delay: 500, max_asset_size: 50,
-		disable_url_preview: false, send_large_photos_as_documents: false, ai_captions: false, chat_action: 'typing',
+		disable_url_preview: true, send_large_photos_as_documents: false, ai_captions: false, chat_action: 'typing',
 		// Discord/Slack shared settings
 		username: '',
 		// ntfy shared settings
@@ -193,6 +194,10 @@
 	function openNew() {
 		form = defaultForm();
 		formType = activeType || 'telegram';
+		// Auto-select first available bot of the chosen type
+		if (formType === 'telegram' && telegramBots.length > 0) form.bot_id = telegramBots[0].id;
+		if (formType === 'email' && emailBots.length > 0) form.email_bot_id = emailBots[0].id;
+		if (formType === 'matrix' && matrixBots.length > 0) form.matrix_bot_id = matrixBots[0].id;
 		editing = null;
 		showTelegramSettings = false;
 		showForm = true;
@@ -289,12 +294,15 @@
 		} catch (err: any) { snackError(err.message); }
 	}
 
+	let blockedBy = $state<BlockedByDetail | null>(null);
 	async function remove(id: number) {
 		try {
 			await api(`/targets/${id}`, { method: 'DELETE' });
 			await load();
 			snackSuccess(t('snack.targetDeleted'));
 		} catch (err: any) {
+			const bb = getBlockedBy(err);
+			if (bb) { blockedBy = bb; return; }
 			error = err.message;
 			snackError(err.message);
 		}
@@ -529,3 +537,5 @@
 	onconfirm={() => { if (confirmDeleteReceiver) { removeReceiver(confirmDeleteReceiver.targetId, confirmDeleteReceiver.receiver.id); confirmDeleteReceiver = null; } }}
 	oncancel={() => confirmDeleteReceiver = null}
 />
+
+<BlockedByModal open={!!blockedBy} detail={blockedBy} onclose={() => blockedBy = null} />