feat: Add load_playlist method to PlayerService and update task handlers for playlist management

app/services/player.py

@@ -429,6 +429,26 @@ class PlayerService:
 
         await self._broadcast_state()
 
+    async def load_playlist(self, playlist_id: int) -> None:
+        """Load a specific playlist by ID."""
+        session = self.db_session_factory()
+        try:
+            playlist_repo = PlaylistRepository(session)
+            playlist = await playlist_repo.get_by_id(playlist_id)
+            if playlist and playlist.id:
+                sounds = await playlist_repo.get_playlist_sounds(playlist.id)
+                await self._handle_playlist_reload(playlist, sounds)
+                logger.info(
+                    "Loaded playlist: %s (%s sounds)",
+                    playlist.name,
+                    len(sounds),
+                )
+            else:
+                logger.warning("Playlist not found: %s", playlist_id)
+        finally:
+            await session.close()
+        await self._broadcast_state()
+
     async def _handle_playlist_reload(
         self,
         current_playlist: Playlist,