Move codegen out of mizan-django: protocol/mizan-generate/

The codegen consumes a schema from any backend and emits typed client
code for any frontend — it doesn't belong inside a backend adapter.
That placement was historical sediment from when there was only a
Django backend; it predates the AFI generalization.

New top-level slot: `protocol/` for protocol-level tooling. Tree is
now:

  backends/    server protocol adapters
  frontends/   client kernel + per-framework adapters
  cores/       shared language-level primitives
  protocol/    protocol-level tooling
  workers/     runtime workers / bridges

Codegen moves to `protocol/mizan-generate/`. Same file layout under
`generator/` (cli.mjs, lib/), preserved via git mv.

Package metadata cleaned up:
- name: "generate" (placeholder) → "mizan-generate"
- description filled in
- type: module (cli.mjs is .mjs ESM, was previously declared "commonjs")
- bin entry added so `npx mizan-generate --config <config.mjs>` works
  once the package is published, instead of `node path/to/cli.mjs`.

Path-reference fixups:
- backends/mizan-django/README.md: `node path/to/...` → `npx mizan-generate`
- backends/mizan-fastapi/README.md: same
- ISSUES.md: file paths in three issue entries
- CLAUDE.md: codegen description + Package Layout section refreshed
  (added protocol/, mizan-fastapi entry, mizan-python entry)
- docs/AFI_ARCHITECTURE.md: Package Layout refreshed identically

Verified codegen runs from new location: regenerated the FastAPI
example harness's api/ output, identical to pre-move.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ISSUES.md

@@ -30,7 +30,7 @@ The kernel stores only `{params, refetch}`. No `data`, `status`, `error`. Every
 ## Remaining High
 
 ### H5. Mutation hooks expose no loading/error state
-**File:** `mizan-django/generate/generator/lib/adapters/react.mjs`
+**File:** `protocol/mizan-generate/generator/lib/adapters/react.mjs`
 Returns bare `useCallback`. No `isPending`, `error`, `isSuccess`.
 
 ### H7. Redis SCAN blocks request path at scale
@@ -38,11 +38,11 @@ Returns bare `useCallback`. No `isPending`, `error`, `isSuccess`.
 Synchronous SCAN at 1M keys: multi-second blocking.
 
 ### H8. Svelte codegen uses Svelte 4 stores
-**File:** `mizan-django/generate/generator/lib/adapters/svelte.mjs`
+**File:** `protocol/mizan-generate/generator/lib/adapters/svelte.mjs`
 Should use Svelte 5 `$state`/`$derived` runes.
 
 ### H9. Svelte destroy() not auto-called
-**File:** `mizan-django/generate/generator/lib/adapters/svelte.mjs`
+**File:** `protocol/mizan-generate/generator/lib/adapters/svelte.mjs`
 Memory leak if user forgets `onDestroy`.
 
 ### H12. Forms triggerValidation captures stale data