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>

react/src/channels/context.tsx

@@ -1,7 +1,7 @@
 'use client'
 
 /**
- * React context for djarea/channels
+ * React context for mizan/channels
  */
 
 import { createContext, useContext, useEffect, useMemo, useRef, useState, type ReactNode } from 'react'