fix: STT consistency — web.py model param, error matching, local provider key

- web.py: pass stt_model from config like discord.py and run.py do
- run.py: match new error messages (No STT provider / not set)
- _transcribe_local: add missing "provider": "local" to return dict

tools/transcription_tools.py

@@ -209,7 +209,7 @@ def _transcribe_local(file_path: str, model_name: str) -> Dict[str, Any]:
             Path(file_path).name, model_name, info.language, info.duration,
         )
 
-        return {"success": True, "transcript": transcript}
+        return {"success": True, "transcript": transcript, "provider": "local"}
 
     except Exception as e:
         logger.error("Local transcription failed: %s", e, exc_info=True)