🐛 fix(window): 修复 Windows 任务栏恢复最大化窗口后字体保持过大

- 问题根因：9848b8b2 禁用 maximised+restore 的 toggle 路径属于过度修复，导致从任务栏点击恢复最大化窗口时 viewport drift 无人修复
- maximised 状态下 Windows API 拒绝 SetSize nudge，唯一可行的修复是 Unmaximise → Maximise 切一次，此前被剪掉
- shouldToggleMaximisedWindowForScaleFix 在 restore + drift 时重新允许 toggle，注释说明去重保护链路
- 重复 toggle 由 inFlight 互斥 + 700ms 冷却 + ratio-change 在 minimisedSeen 上下文合并到 activationTimer 共同防御
- 拆分测试断言：shouldApplyWindowsScaleFix 与 shouldToggleMaximisedWindowForScaleFix 各自独立覆盖 restore 场景

frontend/src/utils/windowStateUi.test.ts

@@ -20,7 +20,13 @@ describe('windowStateUi', () => {
   it('applies the Windows scale fix when a minimized taskbar window is restored with viewport drift', () => {
     expect(shouldApplyWindowsScaleFix('restore', true)).toBe(true);
     expect(shouldApplyWindowsScaleFix('restore', false)).toBe(false);
-    expect(shouldToggleMaximisedWindowForScaleFix('restore', true)).toBe(false);
+  });
+
+  it('toggles maximised windows on restore so taskbar-restored fonts return to the correct size', () => {
+    // maximised 状态下 OS 拒绝 SetSize nudge，唯一可行的修复是切一次 maximise；
+    // 重复触发由 inFlight 互斥 + 700ms 冷却 + ratio-change 合并到 activationTimer 防御。
+    expect(shouldToggleMaximisedWindowForScaleFix('restore', true)).toBe(true);
+    expect(shouldToggleMaximisedWindowForScaleFix('restore', false)).toBe(false);
   });
 
   it('debounces resize-triggered Windows scale checks until window transitions settle', () => {

frontend/src/utils/windowStateUi.ts

@@ -8,10 +8,14 @@ export const shouldApplyWindowsScaleFix = (
   hasViewportScaleDrift: boolean,
 ): boolean => (reason === 'ratio-change' || reason === 'restore') && hasViewportScaleDrift;
 
+// maximised 窗口在 Windows 上无法通过 SetSize nudge 修复 viewport drift（OS 拒绝 resize 已 maximized 窗口）,
+// 唯一能让 WebView2 重新计算缩放的办法是 Unmaximise → Maximise 切换一次。restore 场景（任务栏点击恢复)
+// 必须允许这条路径，否则用户从最小化状态恢复后字体会保持错误大小。重复触发由 inFlight 互斥与 lastFixAt
+// 冷却 + checkDevicePixelRatio 在 minimisedSeen 上下文转发到 activationTimer 共同防御，无需额外禁用 toggle。
 export const shouldToggleMaximisedWindowForScaleFix = (
   reason: WindowScaleFixReason,
   hasViewportScaleDrift: boolean,
-): boolean => reason === 'ratio-change' && hasViewportScaleDrift;
+): boolean => (reason === 'ratio-change' || reason === 'restore') && hasViewportScaleDrift;
 
 export const resolveWindowsScaleCheckDelayMs = (trigger: WindowsScaleCheckTrigger): number =>
   trigger === 'resize' ? 240 : 0;