Fix protocol mismatch + add SSR hydration to codegen

Three bugs fixed:

1. MizanProvider.call() read data.data but server returns data.result.
   Now reads data.result and processes data.invalidate for server-driven
   invalidation (triggering refetch on mounted context providers).

2. GlobalContextLoader expected {error, data} wrapper but context GET
   returns raw bundled data. Fixed to iterate response directly.

3. Named context providers had same wrapper assumption. Fixed to
   setData(result) directly.

Two features added:

1. SSR hydration: GlobalContextLoader checks window.__MIZAN_SSR_DATA__
   on mount. If present, populates contexts from it and skips fetch.

2. SSR hydration: Named context providers check __MIZAN_SSR_DATA__ in
   useState initializer. If SSR data exists for their functions, they
   render immediately without fetching.

3. Server-driven invalidation in MizanProvider.call(): reads the
   invalidate array from mutation responses and triggers refetch on
   mounted providers. Generated mutation hooks' hardcoded invalidation
   is now redundant but idempotent — both paths coexist safely.

Also fixed FunctionSuccessResponse type to match new protocol:
  { result: T, invalidate?: [...] }

373 Django + 33 React tests pass.

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

packages/mizan-react/src/client/index.ts

@@ -528,8 +528,8 @@ import { DjangoError, type FunctionErrorResponse } from '../errors'
  * Success response from a server function
  */
 export interface FunctionSuccessResponse<T> {
-    error: false
-    data: T
+    result: T
+    invalidate?: Array<string | { context: string; params: Record<string, any> }>
 }
 
 /**
@@ -580,6 +580,6 @@ export async function httpFunctionCall<TInput = unknown, TOutput = unknown>(
         throw new DjangoError(data)
     }
 
-    return data.data
+    return (data as FunctionSuccessResponse<TOutput>).result
 }