Flatten to three packages + extract mizan-runtime

packages/
  mizan-runtime/   Framework-agnostic state engine (~150 lines)
                   Context registry, batched invalidation, fetch primitives
  mizan-django/    Django server adapter (was packages/mizan-rpc/adapters/django/)
                   Codegen moved to mizan-django/generate/
  mizan-react/     React adapter (was packages/mizan-csr/adapters/react/)

Removed premature abstractions: mizan-ast, mizan-schema, mizan-rpc,
mizan-csr, mizan-ssr stub packages. The actual architecture is three
concrete packages, not five abstract layers.

mizan-runtime implements the v1 spec: registerContext with params,
scoped invalidation via microtask batching, server-driven invalidation
from mutation responses, mizanFetch for context bundles, mizanCall for
mutations.

264 Django + 33 React tests pass.

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

packages/mizan-react/vitest.config.ts

@@ -0,0 +1,27 @@
+import { defineConfig } from 'vitest/config'
+import path from 'path'
+
+export default defineConfig({
+    resolve: {
+        alias: {
+            'mizan/channels': path.resolve(__dirname, 'src/channels/index.ts'),
+            'mizan/client/react': path.resolve(__dirname, 'src/client/react.ts'),
+            'mizan/client/nextjs': path.resolve(__dirname, 'src/client/nextjs.tsx'),
+            'mizan/client': path.resolve(__dirname, 'src/client/index.ts'),
+            'mizan/jwt': path.resolve(__dirname, 'src/jwt/index.ts'),
+            'mizan/allauth/nextjs': path.resolve(__dirname, 'src/allauth/nextjs.tsx'),
+            'mizan/allauth': path.resolve(__dirname, 'src/allauth/index.ts'),
+            'mizan': path.resolve(__dirname, 'src/index.ts'),
+        },
+    },
+    test: {
+        globals: true,
+        environment: 'jsdom',
+        setupFiles: ['./vitest.setup.ts'],
+        include: ['src/**/*.test.{ts,tsx}'],
+        exclude: [
+            // Requires @/api/generated.mizan.schema.json from consuming project
+            'src/jwt/__tests__/contract.test.ts',
+        ],
+    },
+})