DropSpace v0.2.1-preview.3

DropSpace v0.2.1-preview.3 — Zero-flicker Windows startup

This Preview fixes a lifecycle regression that briefly displayed the main window during Windows sign-in startup. The --startup path now creates the stable main-window HWND required by background services without showing or activating the main window.

Startup behavior

• Keeps the main window hidden for the entire --startup initialization path instead of activating it and hiding it afterward.
• Preserves tray initialization, clipboard monitoring, Dynamic Island/Overlay initialization, update checks, and the single-instance activation pipeline.
• Keeps normal launches visible and allows tray Open or a redirected second launch to show and activate the existing main window.
• Keeps Share Target activation hidden.

Regression coverage

• Adds a Win32 startup visibility check that enumerates the DropSpace process's top-level windows and verifies that the main DropSpace window is not visible after startup initialization.
• Continues to run portable executable smoke coverage in both English and Simplified Chinese resource contexts.
• Preserves the existing installer, upgrade, uninstall, overlay, clipboard, and single-instance validation paths.

中文说明

• 修复 Windows 登录后开机自启动时主窗口短暂闪现的问题；--startup 路径从创建到后台就绪都不会显示或激活主窗口。
• 托盘、剪贴板监听、灵动岛、更新检查和单实例重定向仍会正常初始化。
• 普通启动、托盘打开以及再次运行 EXE 仍可正常显示并激活已有主窗口。
• 新增 Win32 主窗口可见性回归验证，并继续在英文与简体中文资源环境运行完整 Smoke 测试。