ProjectManager.open() now saves app.lastProject to user settings.
Boot calls openLast() instead of opening cwd — first launch shows
the welcome screen, subsequent launches restore the last project
directly into Claude. The welcome "Open project" button shows a
modal path-entry dialog that validates against git and activates
the Claude tab on success. Removed the dead "New Claude session"
button since secondary sessions are spawned via command palette.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>