Handle missing rawResponse in transcription messages (#2623)

* Handle missing rawResponse in transcription messages

- Use message.get('rawResponse', {}) to safely access rawResponse field
- Default is_final to False when rawResponse is missing
- Add proper type annotations for better code clarity
- Minor import formatting cleanup

This prevents KeyError crashes when transcription messages from Daily's API
don't include the rawResponse field in edge cases.

* docs: add changelog line

CHANGELOG.md

@@ -39,6 +39,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add additional fixups to Mistral context messages to ensure they meet
   Mistral-specific requirements, avoiding Mistral "invalid request" errors.
 
+- Fixed `DailyTransport` transcription handling to gracefully handle missing
+  `rawResponse` field in transcription messages, preventing KeyError crashes.
+
 ## [0.0.84] - 2025-09-05
 
 ### Added

src/pipecat/transports/daily/transport.py

@@ -61,9 +61,7 @@ try:
         VirtualCameraDevice,
         VirtualSpeakerDevice,
     )
-    from daily import (
-        LogLevel as DailyLogLevel,
-    )
+    from daily import LogLevel as DailyLogLevel
 except ModuleNotFoundError as e:
     logger.error(f"Exception: {e}")
     logger.error(
@@ -2317,7 +2315,7 @@ class DailyTransport(BaseTransport):
         """Handle participant updated events."""
         await self._call_event_handler("on_participant_updated", participant)
 
-    async def _on_transcription_message(self, message):
+    async def _on_transcription_message(self, message: Dict[str, Any]) -> None:
         """Handle transcription message events."""
         await self._call_event_handler("on_transcription_message", message)
 
@@ -2329,9 +2327,10 @@ class DailyTransport(BaseTransport):
 
         text = message["text"]
         timestamp = message["timestamp"]
-        is_final = message["rawResponse"]["is_final"]
+        raw_response = message.get("rawResponse", {})
+        is_final = raw_response.get("is_final", False)
         try:
-            language = message["rawResponse"]["channel"]["alternatives"][0]["languages"][0]
+            language = raw_response["channel"]["alternatives"][0]["languages"][0]
             language = Language(language)
         except KeyError:
             language = None