Rename djarea to mizan and fix React casing conventions

Rename the package from djarea to mizan across the entire codebase —
Python package, React library, generators, tests, and examples. Fix
JSX/hook casing (MizanProvider, useMizan, etc.) that broke when the
original PascalCase names were lowercased during the rename.

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

example/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.mizan_clients  # noqa: F401