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>

package.json

@@ -1,5 +1,5 @@
 {
-  "name": "djarea",
+  "name": "mizan",
   "version": "1.0.0",
   "description": "Django + React server functions framework.",
   "main": "index.js",