feat: add WeChat QR code login and AGP WebSocket channel plugin

- Auth module: WeChat OAuth2 scan-to-login flow with terminal QR code
- Token persistence to ~/.openclaw/wechat-access-auth.json (chmod 600)
- Token resolution: config > saved state > interactive login
- Invite code verification (configurable bypass)
- Production/test environment support
- AGP WebSocket client with heartbeat, reconnect, wake detection
- Message handler: Agent dispatch with streaming text and tool calls
- Random device GUID generation (persisted, no real machine ID)

http/index.ts

@@ -0,0 +1,59 @@
+// ============================================
+// Fuwuhao (微信服务号) 模块导出
+// ============================================
+
+// 类型定义
+export type {
+  AgentEventPayload,
+  FuwuhaoMessage,
+  SimpleAccount,
+  CallbackPayload,
+  StreamChunk,
+  StreamCallback,
+} from "./types.js";
+
+// 加密解密工具
+export type {
+  VerifySignatureParams,
+  DecryptMessageParams,
+} from "./crypto-utils.js";
+export {
+  verifySignature,
+  decryptMessage,
+} from "./crypto-utils.js";
+
+// HTTP 工具
+export {
+  parseQuery,
+  readBody,
+  isFuwuhaoWebhookPath,
+} from "./http-utils.js";
+
+// 回调服务
+export {
+  sendToCallbackService,
+} from "./callback-service.js";
+
+// 消息上下文
+export type {
+  MessageContext,
+} from "./message-context.js";
+export {
+  buildMessageContext,
+} from "./message-context.js";
+
+// 消息处理器
+export {
+  handleMessage,
+  handleMessageStream,
+} from "./message-handler.js";
+
+// Webhook 处理器（主入口）
+export {
+  handleSimpleWecomWebhook,
+} from "./webhook.js";
+
+// Runtime
+export {
+  getWecomRuntime,
+} from "../common/runtime.js";