修复 AGC 发布入口键盘焦点不可辨认

- :focus-visible 保留 brightness 反馈并补 2px 可见 outline 与 2px 偏移
- hover 与 focus-visible 拆成独立规则，避免 outline:none 覆盖焦点环

apps/ai-game-creator-shell/src/styles.css

@@ -12862,12 +12862,18 @@ button.design-workspace-tree__entry:hover,
 
 .game-workbench-chat
   .project-chat-surface.is-direct-codex
-  .project-chat-publish-trigger:hover:not(:disabled),
+  .project-chat-publish-trigger:hover:not(:disabled) {
+  filter: brightness(1.05);
+}
+
+/* 键盘焦点要有可辨认的指示：仅靠 5% 亮度差在实心主色胶囊上几乎看不出来，保留亮度反馈的同时补一圈
+   可见 outline；`:focus-visible` 只在键盘/辅助技术聚焦时命中，不会给鼠标点击加环。 */
 .game-workbench-chat
   .project-chat-surface.is-direct-codex
   .project-chat-publish-trigger:focus-visible {
   filter: brightness(1.05);
-  outline: none;
+  outline: 2px solid var(--platform-button-primary-border);
+  outline-offset: 2px;
 }
 
 .game-workbench-chat