[Bug]: Open in → File Explorer on Windows ignores the user's default file manager (always launches explorer.exe)#17323

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/server

Steps to reproduce

1. On Windows, set a third-party file manager as the default folder handler (e.g. File Pilot, which registers HKCU\Software\Classes\Directory\shell\open\command).
2. Confirm it works system-wide: Start-Process C:\some\folder opens the folder in that file manager.
3. In T3 Code, use Open in → File Explorer on a project.

Expected behavior

The folder opens in the default file manager, the same as any other shell "open" of a folder.

Actual behavior

Windows File Explorer always opens. fileManagerCommandForPlatform in apps/server/src/process/externalLauncher.ts returns the literal explorer for win32, and explorer.exe <dir> bypasses the Directory\shell\open verb. Verified on the same machine:

Possible fix: open the path through the shell on win32 instead of spawning explorer directly. The launcher already does this for browser targets (resolveWindowsBrowserLaunch). File targets keep their current behaviour, since explorer <file> already hands the file to its default app.

Impact

Minor bug or occasional failure

Version or commit

Desktop nightly 0.0.46 (code path present on main at 9b0df135)

Environment

Windows 11 Pro 10.0.26200, File Pilot 0.6.3

Workaround

None inside T3 Code; open the folder manually in the file manager.