fix(prompt)+feat(gateway): platform-hint truth pass + universal voice-bubble transcode (all 22 hints source-verified) (#97873)

* fix(prompt): platform-hint truth pass — CLI/TUI file-delivery reality (paths/URLs only, MEDIA: prints literally), CLI no-markdown verified live, Slack/Discord markdown+tables truth, shared local-cron constant

* feat(gateway): universal voice-bubble delivery — shared transcode_to_ogg_opus; telegram [[audio_as_voice]] any-format; feishu native voice; hints to new truth

* chore: delete the webui ghost hint (tombstone comment, audit-verified); sync send_voice signature pin in tts routing test

plugins/platforms/feishu/adapter.py

@@ -2247,15 +2247,36 @@ class FeishuAdapter(BasePlatformAdapter):
         metadata: Optional[Dict[str, Any]] = None,
         **kwargs,
     ) -> SendResult:
-        """Send audio to Feishu as a file attachment plus optional caption."""
-        return await self._send_uploaded_file_message(
-            chat_id=chat_id,
-            file_path=audio_path,
-            reply_to=reply_to,
-            metadata=metadata,
-            caption=caption,
-            outbound_message_type="audio",
-        )
+        """Send audio to Feishu as a native voice message (opus) or file.
+
+        Feishu's voice channel only accepts Opus (msg_type='audio' with an
+        opus upload). Non-opus audio (mp3/wav/flac/...) is transcoded on the
+        fly via the shared ffmpeg engine so audio actually arrives as a
+        playable voice message; when ffmpeg is unavailable the original
+        file is sent as a file attachment (previous behavior).
+        """
+        transcoded_path: Optional[str] = None
+        ext = Path(audio_path).suffix.lower()
+        if ext not in _FEISHU_OPUS_UPLOAD_EXTENSIONS:
+            from gateway.platforms.base import transcode_to_ogg_opus
+            transcoded_path = await asyncio.to_thread(transcode_to_ogg_opus, audio_path)
+            if transcoded_path:
+                audio_path = transcoded_path
+        try:
+            return await self._send_uploaded_file_message(
+                chat_id=chat_id,
+                file_path=audio_path,
+                reply_to=reply_to,
+                metadata=metadata,
+                caption=caption,
+                outbound_message_type="audio",
+            )
+        finally:
+            if transcoded_path:
+                try:
+                    os.unlink(transcoded_path)
+                except OSError:
+                    pass
 
     async def send_document(
         self,