feat: add WeChat channel integration (#1869)

* feat: add WeChat channel integration

* fix(backend): recover stale channel threads and align upload artifact handling

* refactor(wechat): reduce scope and restore QR bootstrap

* fix(backend): sort manager imports for Ruff lint

* fix(tests): add missing patch import in test_channels.py

* Update backend/app/channels/wechat.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update backend/app/channels/manager.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* fix(wechat): streamline allowed file extensions initialization and clean up test file

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

backend/app/channels/manager.py

@@ -8,6 +8,7 @@ import mimetypes
 import re
 import time
 from collections.abc import Awaitable, Callable, Mapping
+from pathlib import Path
 from typing import Any
 
 import httpx
@@ -37,6 +38,7 @@ CHANNEL_CAPABILITIES = {
     "feishu": {"supports_streaming": True},
     "slack": {"supports_streaming": False},
     "telegram": {"supports_streaming": False},
+    "wechat": {"supports_streaming": False},
     "wecom": {"supports_streaming": True},
 }
 
@@ -78,7 +80,24 @@ async def _read_wecom_inbound_file(file_info: dict[str, Any], client: httpx.Asyn
     return decrypt_file(data, aeskey)
 
 
+async def _read_wechat_inbound_file(file_info: dict[str, Any], client: httpx.AsyncClient) -> bytes | None:
+    raw_path = file_info.get("path")
+    if isinstance(raw_path, str) and raw_path.strip():
+        try:
+            return await asyncio.to_thread(Path(raw_path).read_bytes)
+        except OSError:
+            logger.exception("[Manager] failed to read WeChat inbound file from local path: %s", raw_path)
+            return None
+
+    full_url = file_info.get("full_url")
+    if isinstance(full_url, str) and full_url.strip():
+        return await _read_http_inbound_file({"url": full_url}, client)
+
+    return None
+
+
 register_inbound_file_reader("wecom", _read_wecom_inbound_file)
+register_inbound_file_reader("wechat", _read_wechat_inbound_file)
 
 
 class InvalidChannelSessionConfigError(ValueError):

backend/app/channels/service.py

@@ -18,6 +18,7 @@ _CHANNEL_REGISTRY: dict[str, str] = {
     "feishu": "app.channels.feishu:FeishuChannel",
     "slack": "app.channels.slack:SlackChannel",
     "telegram": "app.channels.telegram:TelegramChannel",
+    "wechat": "app.channels.wechat:WechatChannel",
     "wecom": "app.channels.wecom:WeComChannel",
 }