fix: pass ref_msg content as structured ReplyTo fields for inbound_meta

[ralf003]

Summary

When a user sends a message that quotes another message (ref_msg), the plugin previously only prepended the quoted content as [引用: ...] prefix in the Body text. This meant the quoted content did not appear in the framework's structured inbound_meta (untrusted reply target block) that buildInboundUserContextPrefix() generates from ReplyToBody / ReplyToId fields.

Root Cause

The weixinMessageToMsgContext() function extracted ref_msg content solely into the Body text prefix. The OpenClaw core framework uses MsgContext fields like ReplyToBody, ReplyToId, ReplyToSender, ReplyToIsQuote to include the quoted message as a structured "Reply target of current user message (untrusted, for context)" block in the agent's inbound_meta. These fields were never populated by the weixin plugin.

Changes

• Add ReplyToBody, ReplyToId, ReplyToSender, ReplyToIsQuote fields to WeixinMsgContext type
• Extract ref_msg content and populate these fields in weixinMessageToMsgContext() so the framework includes the quoted message in the untrusted reply target metadata block
• Refactor: extract extractRefBody() helper from bodyFromItemList() to eliminate duplicated ref_msg content extraction logic

Verification

• npm run build — clean
• npm test — 396/397 pass (1 pre-existing Windows path separator issue in state-dir.test.ts)
• Inbound tests (src/messaging/inbound.test.ts) — all 25 pass
• TypeScript: tsc --noEmit — clean

Closes #222

[NewFuture]

The current community-maintained openclaw-weixin v3.0.1 has partial overlap with this PR, but this PR has not been fully ported:

https://github.com/NewFuture/openclaw-weixin

Currently released behavior preserves quoted text in the message body using the [引用: ...] prefix (including voice STT quote handling). However, it does not populate the structured ReplyToBody, ReplyToId, ReplyToSender, or ReplyToIsQuote fields requested here. Therefore structured inbound_meta support remains outstanding, and this PR is still valuable.

For users who only need the existing body-level quote support, the community package can be installed/replaced in place (requires OpenClaw >=2026.6.1; do not uninstall the official package first):

openclaw plugins install npm:openclaw-weixin --force

The plugin/channel ID and state paths are unchanged, so this normally preserves existing configuration and login state.

For clarity: the linked repository/package is a community-maintained distribution, not the official Tencent/Weixin release. This upstream Tencent PR is still open, and this comment does not claim that its structured metadata change has been merged.