Major refactor of ManaCore's (app) layout for guest mode support:
- New createGuestMode() composable in shared-stores — encapsulates
welcome modal state, nudge timer, and notifications in one call
- Replace monolith onMount with AuthGate + handleAuthReady callback:
Phase A (auth-independent): DB init, migration, uload, dashboard
Phase B (auth-dependent): sync, user settings, onboarding
Phase C (guest-only): welcome modal + registration nudge
- Root route / always redirects to /home (no auth check)
- PillNav shows login button for guests, user email for auth users
- GuestWelcomeModal with manacore-specific features
- SessionWarning only renders for authenticated users
- Proper cleanup via onDestroy
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>