fix: 修复内存泄漏和添加保存按钮加载状态

- router.js: 防止 hashchange 监听器重复绑定
- sidebar.js: 用事件委托替代每次重新绑定事件
- logs.js: 搜索定时器提升为模块级变量，添加 cleanup 导出
- models/agents/gateway/mcp: 保存按钮添加 disabled + 加载文本

src/router.js

@@ -5,6 +5,7 @@ const routes = {}
 let _contentEl = null
 let _loadId = 0
 let _currentCleanup = null
+let _initialized = false
 
 export function registerRoute(path, loader) {
   routes[path] = loader
@@ -16,7 +17,10 @@ export function navigate(path) {
 
 export function initRouter(contentEl) {
   _contentEl = contentEl
-  window.addEventListener('hashchange', () => loadRoute())
+  if (!_initialized) {
+    window.addEventListener('hashchange', () => loadRoute())
+    _initialized = true
+  }
   loadRoute()
 }