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-django/pyproject.toml

@@ -13,6 +13,9 @@ dependencies = [
 ]
 
 [project.optional-dependencies]
+cache = [
+    "redis>=5.0",
+]
 channels = [
     "channels>=4.0",
     "channels-redis>=4.0",