Track pending assets for delayed processing events

- Add _pending_asset_ids to track assets detected but not yet processed
- Fire events when pending assets become processed (thumbhash available)
- Fixes issue where videos added during transcoding never triggered events
- Add debug logging for change detection and pending asset tracking
- Document external domain feature in README

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

custom_components/immich_album_watcher/coordinator.py

@@ -204,19 +204,39 @@ class AssetInfo:
         Returns:
             True if asset is fully processed and not trashed/offline, False otherwise
         """
+        asset_id = data.get("id", "unknown")
+        asset_type = data.get("type", "unknown")
+        is_offline = data.get("isOffline", False)
+        is_trashed = data.get("isTrashed", False)
+        thumbhash = data.get("thumbhash")
+
+        _LOGGER.debug(
+            "Asset %s (%s): isOffline=%s, isTrashed=%s, thumbhash=%s",
+            asset_id,
+            asset_type,
+            is_offline,
+            is_trashed,
+            bool(thumbhash),
+        )
+
         # Exclude offline assets
-        if data.get("isOffline", False):
+        if is_offline:
+            _LOGGER.debug("Asset %s excluded: offline", asset_id)
             return False
 
         # Exclude trashed assets
-        if data.get("isTrashed", False):
+        if is_trashed:
+            _LOGGER.debug("Asset %s excluded: trashed", asset_id)
             return False
 
         # Check if thumbnails have been generated
         # This works for both photos and videos - Immich always generates thumbnails
         # Note: The API doesn't expose video transcoding status (encodedVideoPath),
         # but thumbhash is sufficient since Immich generates thumbnails for all assets
-        return bool(data.get("thumbhash"))
+        is_processed = bool(thumbhash)
+        if not is_processed:
+            _LOGGER.debug("Asset %s excluded: no thumbhash", asset_id)
+        return is_processed
 
 
 @dataclass
@@ -331,6 +351,7 @@ class ImmichAlbumWatcherCoordinator(DataUpdateCoordinator[AlbumData | None]):
         self._telegram_cache = telegram_cache
         self._persisted_asset_ids: set[str] | None = None
         self._external_domain: str | None = None  # Fetched from server config
+        self._pending_asset_ids: set[str] = set()  # Assets detected but not yet processed
 
     @property
     def immich_url(self) -> str:
@@ -824,11 +845,16 @@ class ImmichAlbumWatcherCoordinator(DataUpdateCoordinator[AlbumData | None]):
                         elif removed_ids and not added_ids:
                             change_type = "assets_removed"
 
-                        added_assets = [
-                            album.assets[aid]
-                            for aid in added_ids
-                            if aid in album.assets
-                        ]
+                        added_assets = []
+                        for aid in added_ids:
+                            if aid not in album.assets:
+                                continue
+                            asset = album.assets[aid]
+                            if asset.is_processed:
+                                added_assets.append(asset)
+                            else:
+                                # Track unprocessed assets for later
+                                self._pending_asset_ids.add(aid)
 
                         change = AlbumChange(
                             album_id=album.id,
@@ -885,12 +911,54 @@ class ImmichAlbumWatcherCoordinator(DataUpdateCoordinator[AlbumData | None]):
         added_ids = new_state.asset_ids - old_state.asset_ids
         removed_ids = old_state.asset_ids - new_state.asset_ids
 
-        # Only include fully processed assets in added_assets
-        added_assets = [
-            new_state.assets[aid]
-            for aid in added_ids
-            if aid in new_state.assets and new_state.assets[aid].is_processed
-        ]
+        _LOGGER.debug(
+            "Change detection: added_ids=%d, removed_ids=%d, pending=%d",
+            len(added_ids),
+            len(removed_ids),
+            len(self._pending_asset_ids),
+        )
+
+        # Track new unprocessed assets and collect processed ones
+        added_assets = []
+        for aid in added_ids:
+            if aid not in new_state.assets:
+                _LOGGER.debug("Asset %s: not in assets dict", aid)
+                continue
+            asset = new_state.assets[aid]
+            _LOGGER.debug(
+                "New asset %s (%s): is_processed=%s, filename=%s",
+                aid,
+                asset.type,
+                asset.is_processed,
+                asset.filename,
+            )
+            if asset.is_processed:
+                added_assets.append(asset)
+            else:
+                # Track unprocessed assets for later
+                self._pending_asset_ids.add(aid)
+                _LOGGER.debug("Asset %s added to pending (not yet processed)", aid)
+
+        # Check if any pending assets are now processed
+        newly_processed = []
+        for aid in list(self._pending_asset_ids):
+            if aid not in new_state.assets:
+                # Asset was removed, no longer pending
+                self._pending_asset_ids.discard(aid)
+                continue
+            asset = new_state.assets[aid]
+            if asset.is_processed:
+                _LOGGER.debug(
+                    "Pending asset %s (%s) is now processed: filename=%s",
+                    aid,
+                    asset.type,
+                    asset.filename,
+                )
+                newly_processed.append(asset)
+                self._pending_asset_ids.discard(aid)
+
+        # Include newly processed pending assets
+        added_assets.extend(newly_processed)
 
         # Detect metadata changes
         name_changed = old_state.name != new_state.name