Restore documentation layer — match current substrate

ROADMAP: done items moved out of "Next" (codegen rewrite, SSR bridge,
edge manifest, X-Mizan-Invalidate, return-type branching, affects_params,
kernel extraction, two-stage codegen, mizan-ts). Real "Next" in:
framework-adapter wrapper layer (MizanContext + useMizan + DjangoError
on top of the kernel) for React/Vue/Svelte; A1–A4 from ISSUES.md.

CLAUDE: 4-package layout replaced with the actual 7-package layered
architecture (backend protocol adapters + frontend kernel + framework
adapters + SSR worker). "STALE codegen" section rewritten to describe
what's emitted vs. the wrapper layer that isn't yet.

docs/ now tracked (6 files). AFI_ARCHITECTURE rewritten — replaced
the speculative `mizan-ast`/`mizan-csr`/`mizan-rpc`/`mizan-schema`
package names with the real layout, dropped KDL-schema language for
the actual schema-export format. The other 5 docs/ files were already
current and are tracked as-is.

ARCHITECTURE-REWORK.md deleted — same expert review is re-tracked in
the fresher ISSUES.md, two parallel trackers was sediment.

README.md deleted — drift was beyond surgical fixes (`mizan_clients.py`
convention, `<DjangoContext>` provider, removed `@compose` and
`context='local'`, wrong codegen output filenames, 3-package structure
vs. 7). Rewrite waits for the wrapper-layer codegen to land so
user-facing examples reflect reality.

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

docs/AFI_ARCHITECTURE.md

@@ -0,0 +1,77 @@
+# AFI Architecture
+
+Mizan is an **Application Framework Interface (AFI)** — the
+server-client unification layer.
+
+## Package layout
+
+Two layers per side. Independent packages, single shared protocol.
+
+**Backend protocol adapters** — implement the wire protocol on a
+server stack:
+
+| Package | Role |
+|---|---|
+| `mizan-django` | Django adapter |
+| `mizan-ts` | TypeScript adapter (proves the protocol is language-agnostic) |
+
+**Frontend kernel + framework adapters** — the kernel is the
+imperative client primitive set; each framework adapter wraps the
+kernel in its own idiomatic constructs:
+
+| Package | Role |
+|---|---|
+| `mizan-runtime` | Framework-agnostic client kernel — owns data, status, error; adapters subscribe |
+| `mizan-react` | React contexts + hooks over the kernel |
+| `mizan-vue` | Vue composables over the kernel |
+| `mizan-svelte` | Svelte stores/runes over the kernel |
+
+**SSR worker:**
+
+| Package | Role |
+|---|---|
+| `mizan-ssr` | Bun subprocess used by the Django template backend |
+
+## Two orthogonal products
+
+- **RPC** — typed client generation via codegen
+- **SSR** — server rendering via the Bun bridge
+
+Independent and composable. Either ships standalone; together they
+compose.
+
+## Kernel model
+
+The client kernel (`mizan-runtime`) is the one hard thing. Per-
+framework adapters are thin idiomatic wrappers around it. Codegen
+emits typed bindings against the framework adapter's surface, not
+against the raw kernel — so a React developer gets `useEcho()` and
+`<MizanContext>`, a Vue developer gets `useEcho()` composables, a
+Svelte developer gets readable stores. Same kernel underneath.
+
+## Schema is load-bearing
+
+The backend exports a JSON schema describing every `@client`-decorated
+function and context (`x-mizan-functions`, `x-mizan-contexts`). The
+schema IS the contract: codegen reads it, the edge manifest derives
+from it, MWT auth gates against it.
+
+## Launch surface
+
+Python (Django) + React. Vue and Svelte ship as v1 alongside React.
+TypeScript backend (`mizan-ts`) proves the protocol is portable.
+
+## Why the AFI shape
+
+Quadratic ecosystem growth (N server adapters × M client adapters)
+collapses to linear (one adapter per stack) when both sides
+communicate through a shared protocol.
+
+## Invariants
+
+- All cross-package communication goes through the protocol. No
+  direct cross-package dependencies.
+- New adapters land as new packages, not as modifications to existing
+  ones.
+- Framework adapters wrap the kernel in framework idioms — they
+  don't bypass it. Codegen targets the adapter, not the raw kernel.