Restructure repo into five-package AFI architecture

Mizan is an Application Framework Interface (AFI) with five
independent packages:

  packages/
    mizan-ast/       Language layer (source → KDL schema)
    mizan-schema/    IR layer (KDL schema definition)
    mizan-rpc/       Protocol layer (client gen + server adapters)
      adapters/django/   ← was django/
      generator/         ← was react/src/generator/
    mizan-csr/       State layer (client state engine)
      adapters/react/    ← was react/
    mizan-ssr/       Rendering layer (server-side rendering)

Each package is independent. The adapter directories contain the
framework-specific implementations. Stub packages (ast, schema, ssr)
establish the structure for future work.

264 Django tests + 33 React tests pass from new locations.

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

packages/mizan-csr/adapters/react/vitest.setup.ts

@@ -0,0 +1,6 @@
+import { vi } from 'vitest'
+import '@testing-library/jest-dom/vitest'
+
+// Jest compatibility: existing tests use jest.fn(), jest.spyOn(), jest.mock()
+// Vitest's `vi` object has the same API, so we alias it globally.
+;(globalThis as any).jest = vi