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/src/allauth/contexts/ConfigContext.tsx

@@ -0,0 +1,29 @@
+'use client'
+
+import { createContext, ReactNode, useContext, useMemo } from 'react'
+import { AllauthConfig, defaultConfig, createAllauthConfig } from '../config'
+
+const Context = createContext<AllauthConfig>(defaultConfig)
+
+interface ConfigContextProps {
+    children: ReactNode
+    config?: Partial<AllauthConfig>
+}
+
+export function ConfigContext({ children, config }: ConfigContextProps) {
+    // Memoize the merged config to prevent creating new objects on every render
+    const mergedConfig = useMemo(
+        () => config ? createAllauthConfig(config) : defaultConfig,
+        [config]
+    )
+
+    return (
+        <Context value={mergedConfig}>
+            {children}
+        </Context>
+    )
+}
+
+export function useAllauthConfig(): AllauthConfig {
+    return useContext(Context)
+}