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/settings.py

@@ -20,7 +20,7 @@ INSTALLED_APPS = [
     "django.contrib.auth",
     "django.contrib.contenttypes",
     "django.contrib.sessions",
-    "djarea",
+    "mizan",
     "testapp",
 ]