- Extend shared IPC/DesktopApi types with per-project session listing and creation
- Add project store support for per-project sessions, active project metadata,
  and builtin home project descriptors
- Update preload bridge and desktop UI to show project switcher, project-scoped
  session lists, and per-project session actions
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>