refactor: auto-discover channels via pkgutil, eliminate hardcoded registry

nanobot/channels/feishu.py

@@ -244,11 +244,11 @@ class FeishuChannel(BaseChannel):
     """
 
     name = "feishu"
+    display_name = "Feishu"
 
-    def __init__(self, config: FeishuConfig, bus: MessageBus, groq_api_key: str = ""):
+    def __init__(self, config: FeishuConfig, bus: MessageBus):
         super().__init__(config, bus)
         self.config: FeishuConfig = config
-        self.groq_api_key = groq_api_key
         self._client: Any = None
         self._ws_client: Any = None
         self._ws_thread: threading.Thread | None = None
@@ -928,16 +928,10 @@ class FeishuChannel(BaseChannel):
                 if file_path:
                     media_paths.append(file_path)
 
-                # Transcribe audio using Groq Whisper
-                if msg_type == "audio" and file_path and self.groq_api_key:
-                    try:
-                        from nanobot.providers.transcription import GroqTranscriptionProvider
-                        transcriber = GroqTranscriptionProvider(api_key=self.groq_api_key)
-                        transcription = await transcriber.transcribe(file_path)
-                        if transcription:
-                            content_text = f"[transcription: {transcription}]"
-                    except Exception as e:
-                        logger.warning("Failed to transcribe audio: {}", e)
+                if msg_type == "audio" and file_path:
+                    transcription = await self.transcribe_audio(file_path)
+                    if transcription:
+                        content_text = f"[transcription: {transcription}]"
 
                 content_parts.append(content_text)