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.

packages/server/src/notify_bridge_server/services/test_dispatch.py

@@ -79,7 +79,8 @@ async def dispatch_test_notification(
             if locale_map:
                 template_slots = {EventType.SCHEDULED_MESSAGE.value: locale_map}
 
-    # Resolve target config + receivers (same as watcher)
+    # Resolve target config + receivers (same as watcher — this already sets
+    # each receiver.locale from TargetReceiver.locale or TelegramChat override)
     resolved = await _resolve_target(session, target)
 
     target_cfg = TargetConfig(
@@ -95,21 +96,47 @@ async def dispatch_test_notification(
         receivers=resolved["receivers"],
     )
 
+    if not template_slots:
+        return {
+            "success": False,
+            "error": (
+                f"No '{slot_name}' template defined for this target's template config "
+                f"(locale: {locale}). Add the slot under Template Configs."
+            ),
+        }
+
     # Fetch assets and build event
-    event = await _build_event(
-        provider_type=provider.type,
-        provider_config=provider_config,
-        provider_name=provider.name or provider.type,
-        tracker_name=tracker.name or "",
-        tracker_filters=dict(tracker.filters) if tracker.filters else {},
-        collection_ids=collection_ids,
-        test_type=test_type,
-        tracking_config=tracking_config,
-    )
+    try:
+        event = await _build_event(
+            provider_type=provider.type,
+            provider_config=provider_config,
+            provider_name=provider.name or provider.type,
+            tracker_name=tracker.name or "",
+            tracker_filters=dict(tracker.filters) if tracker.filters else {},
+            collection_ids=collection_ids,
+            test_type=test_type,
+            tracking_config=tracking_config,
+        )
+    except Exception as err:  # noqa: BLE001
+        _LOGGER.exception("Test dispatch event build failed")
+        return {"success": False, "error": f"Provider connection failed: {err}"}
     if event is None:
-        return {"success": False, "error": "No data returned from provider"}
+        return {
+            "success": False,
+            "error": (
+                "Provider returned no data. Check that the provider is reachable, "
+                "credentials are valid, and the tracker has collections configured."
+            ),
+        }
+    # Periodic summary only needs album stats (extra.albums), not assets — skip the asset check.
     if not event.added_assets and test_type in ("scheduled", "memory"):
-        return {"success": False, "error": "No matching assets found" + (" for today" if test_type == "memory" else "")}
+        return {
+            "success": False,
+            "error": (
+                "No matching assets found. Verify the tracker's albums contain assets "
+                "that pass the tracking config filters (favorites only, rating, asset type)."
+            ) + (" for today" if test_type == "memory" else ""),
+        }
 
     # Dispatch through the real NotificationDispatcher
     url_cache, asset_cache = await _get_telegram_caches()
@@ -136,6 +163,13 @@ async def _build_event(
     from datetime import datetime, timezone
 
     if provider_type == "immich":
+        if test_type == "periodic":
+            return await _build_immich_periodic_event(
+                provider_config=provider_config,
+                provider_name=provider_name,
+                tracker_name=tracker_name,
+                collection_ids=collection_ids,
+            )
         return await _build_immich_event(
             provider_config=provider_config,
             provider_name=provider_name,
@@ -237,6 +271,76 @@ async def _build_immich_event(
     )
 
 
+async def _build_immich_periodic_event(
+    *,
+    provider_config: dict,
+    provider_name: str,
+    tracker_name: str,
+    collection_ids: list[str],
+) -> ServiceEvent | None:
+    """Build a periodic-summary event (album stats only, no assets).
+
+    Reuses the same shared core utility (`collect_scheduled_assets`) that
+    scheduled/memory tests use, invoked with limit=0 so we get the full
+    ``collections_extra`` block (album name/url/counts/...) without selecting
+    any individual assets — which is exactly what the
+    ``periodic_summary_message`` template renders.
+    """
+    from datetime import datetime, timezone
+    from notify_bridge_core.providers.immich import ImmichServiceProvider
+    from notify_bridge_core.providers.immich.asset_utils import collect_scheduled_assets
+    from notify_bridge_core.providers.immich.models import ImmichAlbumData, SharedLinkInfo
+
+    from .http_session import get_http_session
+    http_session = await get_http_session()
+    immich = ImmichServiceProvider(
+        http_session,
+        provider_config.get("url", ""),
+        provider_config.get("api_key", ""),
+        provider_config.get("external_domain"),
+        provider_name,
+    )
+    if not await immich.connect():
+        return None
+
+    ext_domain = provider_config.get("external_domain") or provider_config.get("url", "")
+
+    albums: dict[str, ImmichAlbumData] = {}
+    shared_links: dict[str, list[SharedLinkInfo]] = {}
+    for album_id in collection_ids:
+        album = await immich.client.get_album(album_id)
+        if album:
+            albums[album_id] = album
+            shared_links[album_id] = await immich.client.get_shared_links(album_id)
+
+    # limit=0 → returns ([], collections_extra) with full per-album stats.
+    _assets, collections_extra = collect_scheduled_assets(
+        albums, shared_links, ext_domain,
+        limit=0,
+        asset_type="all",
+        favorite_only=False,
+        min_rating=0,
+        is_memory=False,
+    )
+
+    first_col = collections_extra[0] if collections_extra else {}
+    return ServiceEvent(
+        event_type=EventType.SCHEDULED_MESSAGE,
+        provider_type=ServiceProviderType.IMMICH,
+        provider_name=provider_name,
+        collection_id=collection_ids[0] if collection_ids else "",
+        collection_name=first_col.get("name", tracker_name),
+        timestamp=datetime.now(timezone.utc),
+        added_assets=[],
+        added_count=0,
+        extra={
+            "collections": collections_extra,
+            "albums": collections_extra,
+            **(first_col if first_col else {}),
+        },
+    )
+
+
 async def _build_native_memory_event(
     immich,
     ext_domain: str,