[Koshindai]

Fix or feature

• Fix
• Feature

What and why

Fixes #1018.

The macOS update sheet now shows the existing build warning and disables its primary action while a game is building. The button becomes available again in the open sheet when the build ends. Download and compatibility errors keep priority over the build warning, and Restart now closes the sheet only when installation succeeds.

Checked

• Tests passed on macOS 27.0.1 (arm64) with Xcode 27.2. The pre-push hook ran the Mac launcher build and the full Swift suite.
• The regression test hosts the real SwiftUI sheet for both an available update and a staged update, then ends the simulated build while the sheet is open. Both cases failed on the original code and passed with the fix.
• Reviewed the native before and after captures, including re-enablement of both buttons when the build ends. The captures use simulated build and release state.

Screenshots

Primary action	Before, during a build	After, during a build
Update now
Restart now

Scope

• No engine files are added.
• The launcher view has before and after screenshots above.
• No keys, game files or data extracted from a game are in the change or the screenshots.

[v0lumehi]

@Koshindai please resolve the merge conflicts, after that we can merge

[Koshindai]

@v0lumehi The merge conflicts with main are resolved and pushed in 4fde2e98. All local checks passed.

[v0lumehi]

Thank you @Koshindai. Your change is part of #1097, the launcher UI overhaul, with you as co-author. Closing this one in favor of it. Please have a look there if something of yours is missing or changed.