refactor: Reorganize Django apps into domain-based structure

Restructured 13 Django apps from flat/mixed organization into 5 logical
domain packages following cookiecutter-django conventions:

- identity/: core (tenant/domain models, middleware, mixins), users
- scheduling/: schedule, contracts, analytics
- communication/: notifications, credits, mobile, messaging
- commerce/: payments, tickets
- platform/: admin, api

Key changes:
- Moved all apps to smoothschedule/smoothschedule/{domain}/{app}/
- Updated all import paths across the codebase
- Updated settings (base.py, multitenancy.py, test.py)
- Updated URL configuration in config/urls.py
- Updated middleware and permission paths
- Preserved app_label in AppConfig for migration compatibility
- Updated CLAUDE.md documentation with new structure

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

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

smoothschedule/create_admin.py

@@ -6,7 +6,7 @@ import django
 os.environ.setdefault("DJANGO_SETTINGS_MODULE", "config.settings.local")
 django.setup()
 
-from smoothschedule.users.models import User
+from smoothschedule.identity.users.models import User
 from rest_framework.authtoken.models import Token
 
 # Create or get a superuser with platform admin role