feat: support WeChat as a first-class IM channel

WeChat needs a QR-paired path instead of bot-token setup, so the adapter layer now includes the iLink protocol calls, desktop pairing UI, server-side bind/unbind APIs, and shared IM command behavior. Empty project history falls back to the user's default work directory so mobile /new works without pre-opening a desktop project.

Constraint: Tencent iLink login returns a URL that the desktop UI must render as a QR image locally
Constraint: IM adapters should keep /new, /projects, status, permission, and default workdir behavior consistent across WeChat, Feishu, and Telegram
Rejected: Require users to paste absolute project paths for first WeChat sessions | mobile onboarding should work from the default user working directory
Confidence: high
Scope-risk: moderate
Directive: Do not change WeChat polling back to overlapping intervals; getupdates is a long-poll endpoint and must remain serialized
Tested: Real WeChat QR scan, inbound /status, outbound reply, and unbind E2E
Tested: bun run check:adapters
Tested: bun run quality:pr
Not-tested: Re-scan live WeChat after the default-workdir fallback tweak; covered by adapter config tests and PR gate

adapters/README.md

@@ -5,6 +5,7 @@
 用户文档已经迁移到 `docs/`，并且以 Desktop Webapp 配置流程为准：
 
 - `docs/im/index.md`
+- `docs/im/wechat.md`
 - `docs/im/telegram.md`
 - `docs/im/feishu.md`
 
@@ -24,7 +25,7 @@ Desktop Webapp Settings
 注意两点：
 
 - IM 配置和配对都在 Desktop Webapp 的 `Settings -> IM 接入`
-- Webapp 不会自动启动 Adapter 进程，仍需手动运行 `bun run telegram` 或 `bun run feishu`
+- Webapp 不会自动启动 Adapter 进程，仍需手动运行 `bun run wechat`、`bun run telegram` 或 `bun run feishu`
 
 ## 快速启动
 
@@ -34,6 +35,8 @@ bun install
 bun run telegram
 # 或
 bun run feishu
+# 或
+bun run wechat
 ```
 
 ## 开发
@@ -46,6 +49,7 @@ bun test
 bun test common/
 bun test telegram/
 bun test feishu/
+bun test wechat/
 ```
 
 ### 目录结构
@@ -59,6 +63,9 @@ adapters/
 ├── feishu/
 │   ├── media.ts           # FeishuMediaService(@larksuiteoapi/node-sdk 封装)
 │   └── extract-payload.ts # 入站 im.message.receive_v1 事件解析
+├── wechat/
+│   ├── protocol.ts        # 微信 iLink QR 登录 / getupdates / sendmessage 协议封装
+│   └── index.ts           # 微信文本聊天 Adapter
 ├── package.json
 ├── tsconfig.json
 └── README.md