refactor: align codebase with EventCrew domain and trim legacy band stack

- Update API: events, users, policies, routes, resources, migrations
- Remove deprecated models/resources (customers, setlists, invitations, etc.)
- Refresh admin app and docs; remove apps/band

Made-with: Cursor

apps/admin/README.md

@@ -20,7 +20,7 @@ pnpm install
 
 ```env
 VITE_API_URL=http://localhost:8000/api/v1
-VITE_APP_NAME="Band Management Admin"
+VITE_APP_NAME="Event Crew Admin"
 ```
 
 4. Start development: