feat: restore windows to their original macOS Spaces on restart

[tnayuki]

Fixes #123517

Summary

• Add electron-osx-spaces as a dependency to save and restore the macOS Space (virtual desktop) each window belongs to
• Use AppKit's native NSWindow state restoration APIs (encodeRestorableStateWithCoder: / restoreStateWithCoder:) via the electron-osx-spaces package
• The restorable state is persisted as base64-encoded data in IWindowState.macOSRestorableState
• No-op on Windows and Linux

Changes

File	Change
package.json	Add electron-osx-spaces to dependencies
window.ts	Add macOSRestorableState field to IWindowState
windowImpl.ts	Encode Space state on quit, restore on window creation

How to test

1. Build and launch Code - OSS on macOS
2. Open multiple windows (Cmd+Shift+N)
3. Drag each window to a different Space (virtual desktop)
4. Quit (Cmd+Q)
5. Relaunch — windows should restore to their original Spaces

Compatibility

• Backwards compatible: macOSRestorableState is optional; old state data works without it
• Cross-platform: electron-osx-spaces returns no-op on non-macOS platforms
• macOS 15+: The package includes a workaround for NSWindowRestoresWorkspaceAtLaunch being broken (FB15644170)

[vs-code-engineering]

📬 CODENOTIFY

The following users are being notified based on files changed in this PR:

@bpasero

Matched files:

• src/vs/platform/window/electron-main/window.ts
• src/vs/platform/windows/electron-main/windowImpl.ts

[tnayuki]

@microsoft-github-policy-service agree