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

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() {