feat(gateway): add WeCom (Enterprise WeChat) platform support (#3847)

Adds WeCom as a gateway platform adapter using the AI Bot WebSocket
gateway for real-time bidirectional communication. No public endpoint
or new pip dependencies needed (uses existing aiohttp + httpx).

Features:
- WebSocket persistent connection with auto-reconnect (exponential backoff)
- DM and group messaging with configurable access policies
- Media upload/download with AES decryption for encrypted attachments
- Markdown rendering, quote context preservation
- Proactive + passive reply message modes
- Chunked media upload pipeline (512KB chunks)

Cherry-picked from PR #1898 by EvilRan with:
- Moved to current main (PR was 300 commits behind)
- Skipped base.py regressions (reply_to additions are good but belong
  in a separate PR since they affect all platforms)
- Fixed test assertions to match current base class send() signature
  (reply_to=None kwarg now explicit)
- All 16 integration points added surgically to current main
- No new pip dependencies (aiohttp + httpx already installed)

Fixes #1898

Co-authored-by: EvilRan <EvilRan@users.noreply.github.com>

tools/cronjob_tools.py

@@ -372,7 +372,7 @@ Important safety rule: cron-run sessions should not recursively schedule more cr
             },
             "deliver": {
                 "type": "string",
-                "description": "Delivery target: origin, local, telegram, discord, slack, whatsapp, signal, matrix, mattermost, homeassistant, dingtalk, feishu, email, sms, or platform:chat_id or platform:chat_id:thread_id for Telegram topics. Examples: 'origin', 'local', 'telegram', 'telegram:-1001234567890:17585', 'discord:#engineering'"
+                "description": "Delivery target: origin, local, telegram, discord, slack, whatsapp, signal, matrix, mattermost, homeassistant, dingtalk, feishu, wecom, email, sms, or platform:chat_id or platform:chat_id:thread_id for Telegram topics. Examples: 'origin', 'local', 'telegram', 'telegram:-1001234567890:17585', 'discord:#engineering'"
             },
             "model": {
                 "type": "string",

tools/send_message_tool.py

@@ -130,6 +130,7 @@ def _handle_send(args):
         "homeassistant": Platform.HOMEASSISTANT,
         "dingtalk": Platform.DINGTALK,
         "feishu": Platform.FEISHU,
+        "wecom": Platform.WECOM,
         "email": Platform.EMAIL,
         "sms": Platform.SMS,
     }
@@ -368,6 +369,8 @@ async def _send_to_platform(platform, pconfig, chat_id, message, thread_id=None,
             result = await _send_dingtalk(pconfig.extra, chat_id, chunk)
         elif platform == Platform.FEISHU:
             result = await _send_feishu(pconfig, chat_id, chunk, thread_id=thread_id)
+        elif platform == Platform.WECOM:
+            result = await _send_wecom(pconfig.extra, chat_id, chunk)
         else:
             result = {"error": f"Direct sending not yet implemented for {platform.value}"}
 
@@ -794,6 +797,33 @@ async def _send_dingtalk(extra, chat_id, message):
         return {"error": f"DingTalk send failed: {e}"}
 
 
+async def _send_wecom(extra, chat_id, message):
+    """Send via WeCom using the adapter's WebSocket send pipeline."""
+    try:
+        from gateway.platforms.wecom import WeComAdapter, check_wecom_requirements
+        if not check_wecom_requirements():
+            return {"error": "WeCom requirements not met. Need aiohttp + WECOM_BOT_ID/SECRET."}
+    except ImportError:
+        return {"error": "WeCom adapter not available."}
+
+    try:
+        from gateway.config import PlatformConfig
+        pconfig = PlatformConfig(extra=extra)
+        adapter = WeComAdapter(pconfig)
+        connected = await adapter.connect()
+        if not connected:
+            return {"error": f"WeCom: failed to connect — {adapter.fatal_error_message or 'unknown error'}"}
+        try:
+            result = await adapter.send(chat_id, message)
+            if not result.success:
+                return {"error": f"WeCom send failed: {result.error}"}
+            return {"success": True, "platform": "wecom", "chat_id": chat_id, "message_id": result.message_id}
+        finally:
+            await adapter.disconnect()
+    except Exception as e:
+        return {"error": f"WeCom send failed: {e}"}
+
+
 async def _send_feishu(pconfig, chat_id, message, media_files=None, thread_id=None):
     """Send via Feishu/Lark using the adapter's send pipeline."""
     try: