Use NOTIFYICON_VERSION_4 in Windows

[justanotheranonymoususer]

Current tooltip limit is 64 chars, really small. Using NOTIFYICON_VERSION_4 will allow to use 128 chars.

[wanggan768q]

+1 for NOTIFYICON_VERSION_4.

Worth highlighting that v4 also unlocks NIF_GUID / guidItem for stable tray-icon identity. Without it, on Windows the shell falls back to caching "show always in notification area" state keyed by the exe's full path + PE signature. NSIS-installed Tauri apps lose users' pinned state on every update because the installer rewrites the exe.

So v4 isn't just about the longer tooltip — it's the prerequisite for fixing tray-pin persistence across updates, which I think is a more impactful UX win.

[Legend-Master]

Hey everyone, just want a quick update that although we didn't migrate to NOTIFYICON_VERSION_4 yet as I planned to do in #331, by setting cbSize alone in #337 allowed both 128 characters tooltip and NIF_GUID (if we do add support for it)