feat(voice): enable TTS on Weixin / DingTalk / WeCom Bot with text-then-voice delivery

- Clear NOT_SUPPORT_REPLYTYPE on weixin, wecom_bot, dingtalk so TTS replies
  are actually synthesized for these channels.
- Wire desire_rtype=VOICE in weixin and wecom_bot _compose_context so the
  always_reply_voice / voice_reply_voice toggles take effect.
- DingTalk: send native sampleAudio (mediaId + duration). The media API
  only accepts ogg/amr, so convert TTS mp3/wav to amr on the fly.
- WeCom Bot: send native voice msgtype via ws (respond + active push),
  converting TTS audio to amr before upload.
- Weixin (ilink): no outbound voice item, deliver TTS as a file attachment.
- chat_channel: when a TEXT reply is converted to VOICE, stash original
  text in context["voice_reply_text"] and send a text bubble before the
  voice reply. Skipped for feishu_streamed and wechatcom_app, which
  already render text alongside the voice.

channel/weixin/weixin_channel.py

@@ -60,6 +60,9 @@ def _save_credentials(cred_path: str, data: dict):
 @singleton
 class WeixinChannel(ChatChannel):
 
+    # ilink bot protocol has no outbound voice item; deliver TTS as a file.
+    NOT_SUPPORT_REPLYTYPE = []
+
     LOGIN_STATUS_IDLE = "idle"
     LOGIN_STATUS_WAITING = "waiting_scan"
     LOGIN_STATUS_SCANNED = "scanned"
@@ -464,6 +467,14 @@ class WeixinChannel(ChatChannel):
             else:
                 context.type = ContextType.TEXT
             context.content = content.strip()
+            if "desire_rtype" not in context and conf().get("always_reply_voice"):
+                context["desire_rtype"] = ReplyType.VOICE
+
+        elif ctype == ContextType.VOICE:
+            if "desire_rtype" not in context and (
+                conf().get("voice_reply_voice") or conf().get("always_reply_voice")
+            ):
+                context["desire_rtype"] = ReplyType.VOICE
 
         return context
 
@@ -486,6 +497,9 @@ class WeixinChannel(ChatChannel):
             self._send_file(reply.content, receiver, context_token)
         elif reply.type in (ReplyType.VIDEO, ReplyType.VIDEO_URL):
             self._send_video(reply.content, receiver, context_token)
+        elif reply.type == ReplyType.VOICE:
+            # ilink has no outbound voice item; deliver TTS as a file attachment.
+            self._send_file(reply.content, receiver, context_token)
         else:
             logger.warning(f"[Weixin] Unsupported reply type: {reply.type}, fallback to text")
             self._send_text(str(reply.content), receiver, context_token)