refactor(Logs): use APP_TARGET to read target websocket addr

refactor(config): use APP_TARGET constant for backend URL configuration

Centralize backend URL configuration by introducing APP_TARGET constant in vite.config.js and using it for both WebSocket connection and API proxy. This improves maintainability by having a single source of truth for the backend address.

src/views/Logs.vue

@@ -61,7 +61,8 @@ export default {
         const connectWebSocket = () => {
             const token = getCookie('token');
             const wsProtocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
-            const wsUrl = `${wsProtocol}//localhost:8080/system/getLogs?token=${token}`;
+            const target = __APP_TARGET__;
+            const wsUrl = `${wsProtocol}//${target}/system/getLogs?token=${token}`;
 
             socket.value = new WebSocket(wsUrl);