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>

frontends/mizan-react/src/channels/index.ts

@@ -0,0 +1,76 @@
+/**
+ * mizan/channels
+ *
+ * Real-time WebSocket communication with Django Channels.
+ * Type-safe bidirectional messaging.
+ *
+ * ## Setup
+ *
+ * ```tsx
+ * // layout.tsx
+ * import { ChannelProvider } from 'mizan/channels'
+ *
+ * export default function Layout({ children }) {
+ *     return (
+ *         <ChannelProvider>
+ *             {children}
+ *         </ChannelProvider>
+ *     )
+ * }
+ * ```
+ *
+ * ## Usage
+ *
+ * ```tsx
+ * // Using generated hooks (recommended)
+ * import { useChatChannel } from '@/api/generated.channels'
+ *
+ * function Chat({ room }) {
+ *     const chat = useChatChannel({ room })
+ *
+ *     chat.status     // 'connecting' | 'connected' | 'disconnected'
+ *     chat.messages   // DjangoMessage[]
+ *     chat.send({ text: 'Hello' })  // Send ReactMessage
+ * }
+ * ```
+ *
+ * ```tsx
+ * // Using raw hook (for custom channels)
+ * import { useChannel } from 'mizan/channels'
+ *
+ * function CustomChannel() {
+ *     const channel = useChannel<
+ *         { room: string },           // Params
+ *         { user: string; text: string },  // DjangoMessage
+ *         { text: string }            // ReactMessage
+ *     >('chat', { room: 'general' })
+ *
+ *     // ...
+ * }
+ * ```
+ */
+
+// Context
+export { ChannelProvider, useChannelContext, useChannelStatus } from './context'
+export type { ChannelProviderProps } from './context'
+
+// Hooks
+export { useChannel, useChannelLatest, useRPC, RPCError } from './hooks'
+export type { UseChannelOptions, RPCClient } from './hooks'
+
+// Connection (for advanced use)
+export { ChannelConnection, getDefaultConnection } from './connection'
+export type {
+    ChannelConnectionOptions,
+    RPCRequest,
+    RPCResponse,
+    RPCSuccessResponse,
+    RPCErrorResponse,
+} from './connection'
+
+// Types
+export type {
+    ConnectionStatus,
+    ChannelSubscription,
+    SubscribeOptions,
+} from './types'