🐛 fix: add warning for unregistered language callbacks in transcription

Author: yokotoka

src/palabra_ai/task/transcription.py

@@ -11,7 +11,7 @@
 from palabra_ai.task.io.base import Io
 
 # from palabra_ai.task.realtime import Realtime
-from palabra_ai.util.logger import debug, error
+from palabra_ai.util.logger import debug, error, warning
 
 
 @dataclass
@@ -69,6 +69,10 @@ async def _process_message(self, msg: Message):
 
             callback = self._callbacks.get(msg.language.code)
             if not callback:
+                warning(
+                    f"No callback registered for language '{msg.language.code}'. "
+                    f"Registered: {list(self._callbacks.keys())}"
+                )
                 return
 
             # Call the callback