Architecture rework: fix protocol bugs, add origin-side cache, document spec

8-expert review identified 3 bugs in shipped code (Vary header hallucination,
fn/function wire key mismatch, max-age=0 defeating PSR) — all fixed with
tests updated across Python and TypeScript.

Added: manifest version field, affects validation, wire format convention,
origin-side cache module (HMAC key derivation, MemoryCache + RedisCache
backends, reverse index for scoped invalidation, executor integration).

16 known issues documented in cache/KNOWN_ISSUES.md from expert review —
critical items (user_id not passed, purge race condition, no Redis error
handling) to be fixed in follow-up.

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

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

@@ -124,7 +124,7 @@ export async function mizanCall(
             'Content-Type': 'application/json',
         },
         credentials: 'same-origin',
-        body: JSON.stringify({ function: functionName, args }),
+        body: JSON.stringify({ fn: functionName, args }),
     })
     if (!res.ok) throw new MizanError(res.status, await res.text())