feat: add dashboard API with quick links and widgets

- Dashboard domain with Quick Links CRUD + reorder endpoints
- Dashboard widgets management endpoints
- Database migrations for quick_links and dashboard_widgets tables
- Static file controller for Organizr widgets
- Default local user when OIDC is disabled
- Domain-based architecture refactor (src/domains/, src/shared/)
- Test suite updated for new structure (285 tests passing)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

alembic/env.py

@@ -13,11 +13,12 @@ from sqlalchemy.ext.asyncio import async_engine_from_config
 from alembic import context
 
 # Import our models and config
-from src.config import get_settings
-from src.db.database import Base
+from src.shared.config import get_settings
+from src.shared.database import Base
 
 # Import all models to ensure they're registered with Base.metadata
-from src.db.models import User, Role, UserRole, UserPreferences, ApiKey  # noqa: F401
+from src.domains.auth.models import User, Role, UserRole, UserPreferences, ApiKey  # noqa: F401
+from src.domains.dashboard.models import QuickLink, DashboardWidget  # noqa: F401
 
 # Alembic Config object
 config = context.config