fix(windows): improve dark titlebar contrast (#78)

Add a dark translucent legibility layer to the native Windows application menu when Dream Skin uses dark appearance.

Increase menu text and icon contrast while retaining the wallpaper and native header geometry. Add the CSS inventory regression and changelog entry.

Co-authored-by: silver <470738257@qq.com>

Author: silvermoon89

windows/CHANGELOG.md

@@ -15,6 +15,7 @@
 ### 修复
 
 - 保留 Codex 原生固定顶栏的定位与层级，避免打开任务侧边面板后开关被推出主区、导致面板无法关闭。
+- 暗色外观下，原生顶部菜单栏现在使用深色半透明可读性层，并提高菜单按钮与图标的文字对比度，避免浅色壁纸让导航项难以辨认。
 - 渲染层现在只在检测到完整 Codex 主界面壳层时启用皮肤；宠物等透明辅助窗口会主动清理主题背景与装饰节点，避免出现遮挡宠物的矩形背景框。
 - 16:9 及更宽图像现在作为侧栏与主区共享的单张整窗背景；首页、任务、插件、计划任务和 Pull Requests 路由使用同一透明顶栏与连续表面，不再在卡片或任务层重复裁切图片。
 - 移除主区原生顶部渐隐和 composer 后方底部渐隐；浅色与深色 composer 均只保留一个可读表面，避免出现双层输入框或不连续底板。

windows/assets/dream-skin.css

@@ -112,6 +112,22 @@ html.codex-dream-skin main.main-surface > header.app-header-tint {
   backdrop-filter: blur(12px) saturate(1.05) !important;
 }
 
+/* Wide art also reaches the native application menu, which sits outside the
+   main surface and needs its own dark-theme legibility layer. */
+html.codex-dream-skin.dream-theme-dark [class~="group/application-menu-top-bar"] {
+  color: var(--dream-text) !important;
+  background: color-mix(in oklab, var(--dream-sidebar) 90%, transparent) !important;
+  border-bottom: 1px solid var(--dream-line-soft) !important;
+  box-shadow: 0 1px 12px color-mix(in oklab, var(--dream-canvas) 72%, transparent) !important;
+  backdrop-filter: blur(16px) saturate(.9) !important;
+}
+
+html.codex-dream-skin.dream-theme-dark [class~="group/application-menu-top-bar"] button,
+html.codex-dream-skin.dream-theme-dark [class~="group/application-menu-top-bar"] svg {
+  color: var(--dream-text) !important;
+  text-shadow: 0 1px 2px color-mix(in oklab, var(--dream-canvas) 82%, transparent) !important;
+}
+
 #codex-dream-skin-chrome {
   display: none !important;
   pointer-events: none !important;

windows/tests/run-tests.ps1

@@ -711,6 +711,7 @@ try {
   foreach ($requiredCss in @(
     'background-image: var(--dream-art)',
     'main.main-surface > header.app-header-tint',
+    '[class~="group/application-menu-top-bar"]',
     '.app-shell-main-content-top-fade',
     '.thread-scroll-container .bg-gradient-to-t.from-token-main-surface-primary',
     '--dream-immersive-composer',