Refactor HAOS integration to use shared core library (Phase 2)

Wire the integration to delegate all HA-independent logic to
immich-watcher-core, eliminating ~2300 lines of duplicated code.

Changes:
- const.py: Import shared constants from core, keep HA-specific ones
- storage.py: Create HAStorageBackend adapter wrapping HA's Store,
  use core TelegramFileCache and NotificationQueue via adapter
- coordinator.py: Delegate to core ImmichClient for API calls,
  detect_album_changes() for change detection, and asset_utils
  for filtering/sorting/URL building. Keep HA-specific event firing.
- sensor.py: Replace ~1300 lines of Telegram code with 15-line
  delegation to core TelegramClient. Keep entity classes unchanged.
- __init__.py: Use factory functions for creating core instances
  with HA storage backends
- manifest.json: Add immich-watcher-core dependency

Integration line count: 3600 -> 1295 lines (-64%)
Zero behavior changes for end users.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

custom_components/immich_album_watcher/__init__.py

@@ -25,7 +25,13 @@ from .const import (
     PLATFORMS,
 )
 from .coordinator import ImmichAlbumWatcherCoordinator
-from .storage import ImmichAlbumStorage, NotificationQueue, TelegramFileCache
+from .storage import (
+    ImmichAlbumStorage,
+    NotificationQueue,
+    TelegramFileCache,
+    create_notification_queue,
+    create_telegram_cache,
+)
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -80,16 +86,16 @@ async def async_setup_entry(hass: HomeAssistant, entry: ImmichConfigEntry) -> bo
     # TTL is in hours from config, convert to seconds
     cache_ttl_seconds = telegram_cache_ttl * 60 * 60
     # URL-based cache for non-Immich URLs or URLs without extractable asset IDs
-    telegram_cache = TelegramFileCache(hass, entry.entry_id, ttl_seconds=cache_ttl_seconds)
+    telegram_cache = create_telegram_cache(hass, entry.entry_id, ttl_seconds=cache_ttl_seconds)
     await telegram_cache.async_load()
     # Asset ID-based cache for Immich URLs — uses thumbhash validation instead of TTL
-    telegram_asset_cache = TelegramFileCache(
+    telegram_asset_cache = create_telegram_cache(
         hass, f"{entry.entry_id}_assets", use_thumbhash=True
     )
     await telegram_asset_cache.async_load()
 
     # Create notification queue for quiet hours
-    notification_queue = NotificationQueue(hass, entry.entry_id)
+    notification_queue = create_notification_queue(hass, entry.entry_id)
     await notification_queue.async_load()
 
     # Store hub reference