Add configurable data providers and localize frontend UI

frontend/src/services/websocket.js

@@ -51,7 +51,7 @@ export class ReadOnlyClient {
       this.reconnectAttempts = 0;
       this.reconnectDelay = this.baseReconnectDelay;
       this.lastPongTime = Date.now();
-      this._safeEmit({ type: "system", content: "Connected to live server" });
+      this._safeEmit({ type: "system", content: "已连接实时数据服务" });
       console.log("WebSocket connected");
       this._startHeartbeat();
     };
@@ -79,7 +79,7 @@ export class ReadOnlyClient {
     };
 
     this.ws.onclose = (event) => {
-      const code = event.code || "Unknown";
+      const code = event.code || "未知";
       console.log(`[WebSocket] Connection closed: Code=${code}, WasClean=${event.wasClean}`);
 
       this._stopHeartbeat();
@@ -96,7 +96,7 @@ export class ReadOnlyClient {
 
         this._safeEmit({
           type: "system",
-          content: "Try to connect to data server..."
+          content: "正在尝试连接数据服务..."
         });
 
         if (this.reconnectTimer) {
@@ -189,4 +189,3 @@ export class ReadOnlyClient {
     this.ws = null;
   }
 }
-