🎨 调整文件列表hover颜色

- 暗色主题：rgba(255, 255, 255, 0.05) 微亮
- 亮色主题：rgba(0, 0, 0, 0.04) 微暗

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/app.html

@@ -932,10 +932,10 @@
       transition: background 0.15s ease;
     }
     .file-list-row:hover {
-      background: rgba(102, 126, 234, 0.08);
+      background: rgba(255, 255, 255, 0.05);
     }
     body.light-theme .file-list-row:hover {
-      background: rgba(102, 126, 234, 0.06);
+      background: rgba(0, 0, 0, 0.04);
     }
 
     /* ========== 危险按钮 ========== */