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)

websocket/index.ts

@@ -0,0 +1,40 @@
+// ============================================
+// WebSocket 模块导出
+// ============================================
+
+// 类型定义
+export type {
+  AGPEnvelope,
+  AGPMethod,
+  ContentBlock,
+  ToolCall,
+  ToolCallKind,
+  ToolCallStatus,
+  ToolLocation,
+  PromptPayload,
+  CancelPayload,
+  UpdatePayload,
+  UpdateType,
+  PromptResponsePayload,
+  StopReason,
+  PromptMessage,
+  CancelMessage,
+  UpdateMessage,
+  PromptResponseMessage,
+  WebSocketClientConfig,
+  ConnectionState,
+  WebSocketClientCallbacks,
+} from "./types.js";
+
+// WebSocket 客户端
+export { WechatAccessWebSocketClient } from "./websocket-client.js";
+
+// 消息处理器
+export { handlePrompt, handleCancel } from "./message-handler.js";
+
+// 消息适配器
+export {
+  extractTextFromContent,
+  promptPayloadToFuwuhaoMessage,
+  buildWebSocketMessageContext,
+} from "./message-adapter.js";