Update IPFS playlist CID in database during streaming for live HLS

- Add on_playlist_update callback to IPFSHLSOutput
- Pass callback through StreamInterpreter to output
- Update database with playlist CID as segments are created
- Enables live HLS redirect to IPFS before rendering completes

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

streaming/stream_sexp_generic.py

@@ -85,6 +85,9 @@ class StreamInterpreter:
         # Error tracking
         self.errors: List[str] = []
 
+        # Callback for live streaming (called when IPFS playlist is updated)
+        self.on_playlist_update: callable = None
+
     def _resolve_name(self, name: str) -> Optional[Path]:
         """Resolve a friendly name to a file path using the naming service."""
         try:
@@ -906,7 +909,8 @@ class StreamInterpreter:
             hls_dir = output[:-9]  # Remove /ipfs-hls suffix
             import os
             ipfs_gateway = os.environ.get("IPFS_GATEWAY_URL", "https://ipfs.io/ipfs")
-            out = IPFSHLSOutput(hls_dir, size=(w, h), fps=fps, audio_source=audio, ipfs_gateway=ipfs_gateway)
+            out = IPFSHLSOutput(hls_dir, size=(w, h), fps=fps, audio_source=audio, ipfs_gateway=ipfs_gateway,
+                               on_playlist_update=self.on_playlist_update)
         else:
             out = FileOutput(output, size=(w, h), fps=fps, audio_source=audio)