Fix lazy audio path resolution for GPU streaming

Audio playback path was being resolved during parsing when database
may not be ready, causing fallback to non-existent path. Now resolves
lazily when stream starts, matching how audio analyzer works.

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

database.py

@@ -244,6 +244,15 @@ async def update_cache_item_ipfs_cid(cid: str, ipfs_cid: str) -> bool:
         return result == "UPDATE 1"
 
 
+async def get_ipfs_cid(cid: str) -> Optional[str]:
+    """Get the IPFS CID for a cache item by its internal CID."""
+    async with pool.acquire() as conn:
+        return await conn.fetchval(
+            "SELECT ipfs_cid FROM cache_items WHERE cid = $1",
+            cid
+        )
+
+
 async def delete_cache_item(cid: str) -> bool:
     """Delete a cache item and all associated data (cascades)."""
     async with pool.acquire() as conn: