Restructure tree by role; rename mizan-runtime → mizan-base

packages/ flattens into:
  backends/   server protocol adapters (mizan-django, mizan-ts)
  frontends/  client kernel + framework adapters (mizan-base, mizan-react, mizan-vue, mizan-svelte)
  workers/    runtime workers (mizan-ssr)
  cores/      shared language-level primitives (empty for now; mizan-python forthcoming)

The frontend kernel (was packages/mizan-runtime, now frontends/mizan-base) is
renamed to reflect its role — it's the shared base that frontend adapters
depend on directly. Reflects the substrate position that per-framework adapters
wrap a single shared kernel; codegen targets the adapter, not the raw kernel.

Path updates landed in: Makefile, two Gitea workflows, Dockerfile.test, four
example/harness config files, .claude/settings.local.json, four docs
(CLAUDE/ISSUES/ROADMAP/AFI_ARCHITECTURE), four codegen templates (stage1 +
react/vue/svelte adapters), and three package.jsons (the mizan-base rename
plus mizan-vue/svelte peerDeps).

Generated files under examples/django-react-site/harness/src/api/ still
reference @mizan/runtime — left as-is; they're regenerated artifacts and
the harness is non-functional pending the React wrapper-layer codegen.

Also folded in a pre-existing fix: the Gitea workflows had
working-directory: react / django pointing at a layout that predates
packages/, never updated.

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

backends/mizan-ts/src/cache/keys.ts

@@ -0,0 +1,57 @@
+/**
+ * Cache key derivation — HMAC-SHA256 over JSON-canonical form.
+ *
+ * Protocol-critical: must produce identical output to Python's derive_cache_key.
+ * Cross-language conformance verified by pin tests.
+ *
+ * Key format: "ctx:{context}:{hmac_hex}" — enables broad purge by prefix scan.
+ */
+
+import { createHmac } from 'crypto'
+
+const CONTEXT_KEY_PREFIX = 'ctx:'
+
+/**
+ * JSON.stringify with recursively sorted keys and no whitespace.
+ * Equivalent to Python's json.dumps(obj, sort_keys=True, separators=(",", ":"))
+ */
+function stableStringify(obj: any): string {
+    if (obj === null || obj === undefined) return 'null'
+    if (typeof obj === 'string') return JSON.stringify(obj)
+    if (typeof obj === 'number' || typeof obj === 'boolean') return String(obj)
+    if (Array.isArray(obj)) {
+        return '[' + obj.map(stableStringify).join(',') + ']'
+    }
+    const keys = Object.keys(obj).sort()
+    const pairs = keys.map(k => JSON.stringify(k) + ':' + stableStringify(obj[k]))
+    return '{' + pairs.join(',') + '}'
+}
+
+/**
+ * Derive a deterministic HMAC-SHA256 cache key.
+ *
+ * Returns "ctx:{context}:{hmac_hex}".
+ */
+export function deriveCacheKey(
+    secret: string,
+    context: string,
+    params: Record<string, any>,
+    userId?: string,
+    rev: number = 0,
+): string {
+    const sortedParams: Record<string, string> = {}
+    for (const [k, v] of Object.entries(params).sort(([a], [b]) => a < b ? -1 : a > b ? 1 : 0)) {
+        sortedParams[k] = String(v)
+    }
+
+    const keyData: Record<string, any> = { c: context, p: sortedParams, r: rev }
+    if (userId !== undefined) {
+        keyData.u = String(userId)
+    }
+
+    const message = stableStringify(keyData)
+    const hmacHex = createHmac('sha256', secret).update(message).digest('hex')
+    return `${CONTEXT_KEY_PREFIX}${context}:${hmacHex}`
+}
+
+export { CONTEXT_KEY_PREFIX }