The WeCom integration adds useful channel support, but there are several issues that should be addressed before merging.

Missing error handling / security concerns:

1. No tests included: This PR adds ~1100 lines of Go code across wecom.go (466 lines) and wecom_app.go (629 lines) with zero test files. At minimum, the AES decryption, signature verification, and XML parsing paths need unit tests — these are security-critical code paths.

2. Config watcher (pkg/config/watcher.go): This adds a 258-line file watcher that is unrelated to WeCom. It should be a separate PR. Mixing orthogonal features makes review harder and increases merge conflict surface.

3. allow_from field inconsistency: The README docs use allow_from (snake_case) for WeCom but some existing channels use allowFrom (camelCase). The config struct should be consistent with the rest of the codebase.

4. Missing context.Context propagation: The WeCom HTTP handler should accept and pass through context.Context for proper cancellation support, consistent with how other channels (LINE, MaixCam) handle it.

5. Hardcoded timeout values: The 5-second WeCom reply deadline is mentioned in docs but I do not see a configurable timeout in the code or config struct. This should be a config option.

6. loop.go changes: The diff shows 18 additions / 21 deletions in loop.go — these changes should be reviewed carefully to ensure they do not affect existing channel behavior. Please describe what changed in the agent loop and why it was necessary for WeCom support.

Please split the config watcher into a separate PR and add tests for the security-critical paths (AES decryption, signature verification).

所有的peer_kind都硬编码为direct，应该存在一些问题。我无法确定，你可以进行相关测试。

1. 所有的群聊消息都会被当作私信处理，直接导致session中会为群聊中的每个用户都创建一个json，也就是说：群聊中的每个用户的llm会话都是独立的。
2. 可能会出现隔离错误，当dm_scope设置为main时，所有的群聊、私聊都会被合并为同一个main会话。

All peer_kind are hardcoded as direct, which likely indicates some issues. I'm not entirely certain; you can conduct relevant tests.

1. All group chat messages are treated as private messages, which directly results in a JSON being created for each user in the group chat within the session. In other words, each user in the group chat has an independent LLM session.
2. Isolation errors may occur. When dm_scope is set to main, all group chats and private chats are merged into the same main session.