refactor(messaging): replace WebSocket with SSE for real-time message handling

Replace WebSocket-based real-time communication with Server-Sent Events (SSE) across the messaging infrastructure. This includes:

- Create new SSEClient datasource to manage SSE connections
- Create new SSEMessageHandler to process SSE events
- Update ProcessMessageUseCase to use SSEClient instead of WebSocketClient
- Update MessageManager and MessageStateManager to work with SSE handlers
- Rename connection state variables from `isWebSocketConnected` to `isSSEConnected`
- Update type definitions in dto.ts (WSEventType → SSEEventType, etc.)
- Delete obsolete WebSocketClient and WebSocketMessageHandler files
- Update comments and documentation to reflect SSE terminology

This refactoring aligns with the backend's SSE implementation for better compatibility with React Native's networking capabilities.

src/data/datasources/SSEClient.ts

@@ -1,6 +1,6 @@
 /**
- * WebSocketClient - WebSocket连接管理
- * 只负责WebSocket连接管理，提供事件驱动架构
+ * SSEClient - SSE连接管理
+ * 只负责SSE连接管理，提供事件驱动架构
  */
 
 import {
@@ -19,8 +19,8 @@ import {
 // 事件处理器类型
 type EventHandler<T> = (data: T) => void;
 
-// WebSocket事件类型
-export interface WebSocketEvents {
+// SSE事件类型
+export interface SSEEvents {
   'chat': WSChatMessage;
   'group_message': WSGroupChatMessage;
   'read': WSReadMessage;
@@ -34,15 +34,15 @@ export interface WebSocketEvents {
   'error': Error;
 }
 
-export type WebSocketEventType = keyof WebSocketEvents;
+export type SSEEventType = keyof SSEEvents;
 
-class WebSocketClient {
-  private handlers: Map<WebSocketEventType, Set<EventHandler<any>>> = new Map();
+class SSEClient {
+  private handlers: Map<SSEEventType, Set<EventHandler<any>>> = new Map();
   private unsubscribeFns: Array<() => void> = [];
   private isInitialized = false;
 
   /**
-   * 初始化WebSocket监听
+   * 初始化SSE监听
    */
   initialize(): void {
     if (this.isInitialized) return;
@@ -113,7 +113,7 @@ class WebSocketClient {
   }
 
   /**
-   * 销毁WebSocket监听
+   * 销毁SSE监听
    */
   destroy(): void {
     this.unsubscribeFns.forEach((fn) => fn());
@@ -125,9 +125,9 @@ class WebSocketClient {
   /**
    * 订阅事件
    */
-  on<T extends WebSocketEventType>(
+  on<T extends SSEEventType>(
     event: T,
-    handler: EventHandler<WebSocketEvents[T]>
+    handler: EventHandler<SSEEvents[T]>
   ): () => void {
     if (!this.handlers.has(event)) {
       this.handlers.set(event, new Set());
@@ -142,9 +142,9 @@ class WebSocketClient {
   /**
    * 触发事件
    */
-  private emit<T extends WebSocketEventType>(
+  private emit<T extends SSEEventType>(
     event: T,
-    data: WebSocketEvents[T]
+    data: SSEEvents[T]
   ): void {
     const handlers = this.handlers.get(event);
     if (handlers) {
@@ -152,7 +152,7 @@ class WebSocketClient {
         try {
           handler(data);
         } catch (error) {
-          console.error(`[WebSocketClient] 事件处理器执行失败: ${event}`, error);
+          console.error(`[SSEClient] 事件处理器执行失败: ${event}`, error);
         }
       });
     }
@@ -166,19 +166,19 @@ class WebSocketClient {
   }
 
   /**
-   * 启动WebSocket连接
+   * 启动SSE连接
    */
   async connect(): Promise<boolean> {
     return sseService.start();
   }
 
   /**
-   * 断开WebSocket连接
+   * 断开SSE连接
    */
   disconnect(): void {
     sseService.stop();
   }
 }
 
-export const webSocketClient = new WebSocketClient();
-export default webSocketClient;
+export const sseClient = new SSEClient();
+export default sseClient;