Rename all djarea references to mizan

- djarea_clients.py → clients.py (both example apps)
- export_djarea_schema → export_mizan_schema (management command)
- djarea.spec.ts → mizan.spec.ts (playwright test)
- fetch.mjs: command name updated
- apps.py/asgi.py: import paths updated
- Removed stale generated.djarea.* artifacts
- Fixed desktop app: asgi.py import, vite config aliases, package.json dep path

373 Django tests pass. Both example apps verified running.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

examples/django-react-site/backend/testapp/apps.py

@@ -6,4 +6,4 @@ class TestAppConfig(AppConfig):
     default_auto_field = "django.db.models.BigAutoField"
 
     def ready(self):
-        import testapp.djarea_clients  # noqa: F401
+        import testapp.clients  # noqa: F401