fix: titlebar dragging area and add double-click to maximize

src/renderer/css/app.css

@@ -46,9 +46,8 @@ body {
   display: flex;
   align-items: center;
   gap: 8px;
-  flex: 1;
   overflow: hidden;
-  -webkit-app-region: no-drag;
+  -webkit-app-region: drag; /* 允许左侧空白和品牌区域拖拽 */
 }
 
 .app-brand {
@@ -60,6 +59,16 @@ body {
   color: var(--accent-color);
   padding: 0 8px;
   letter-spacing: 0.5px;
+  -webkit-app-region: drag;
+  cursor: grab;
+}
+
+.titlebar-drag-spacer {
+  flex: 1;
+  height: 100%;
+  -webkit-app-region: drag; /* 中间大面积空白区域允许拖拽 */
+  cursor: grab;
+  min-width: 40px;
 }
 
 .app-brand-icon {

src/renderer/css/tabs.css

@@ -6,6 +6,7 @@
   overflow-x: auto;
   scrollbar-width: none;
   max-width: calc(100vw - 320px);
+  -webkit-app-region: no-drag;
 }
 
 .tab-bar::-webkit-scrollbar {

src/renderer/index.html

@@ -37,6 +37,9 @@
         </button>
       </div>
 
+      <!-- 中间空白可拖拽区域 -->
+      <div class="titlebar-drag-spacer" id="titlebar-drag-spacer"></div>
+
       <!-- 右侧快速操作按钮与窗口控制 -->
       <div class="titlebar-actions">
         <button class="btn-icon" id="btn-split-h" title="向右水平分屏 (Ctrl+Shift+E)">

src/renderer/js/app.js

@@ -169,6 +169,14 @@ class TerminalApp {
     document.getElementById('win-close')?.addEventListener('click', () => {
       window.terminalAPI.close();
     });
+
+    // 双击标题栏空白处最大化/还原
+    document.getElementById('titlebar-drag-spacer')?.addEventListener('dblclick', () => {
+      window.terminalAPI.maximize();
+    });
+    document.querySelector('.app-brand')?.addEventListener('dblclick', () => {
+      window.terminalAPI.maximize();
+    });
   }
 
   initIpcListeners() {