example(hubs): add public/ asset fixtures and wire the Assets dock into both hubs

The Assets tab now works end-to-end in both hub examples:

- vite-devframe-hub: already mounts the default assets devframe (manages
  <cwd>/public, served by Vite at /). Added a public/ fixture set so the
  tab has real content and previews resolve to Vite own URLs.
- next-devframe-hub: mount the assets devframe with its dir pointed at the
  Next app public/ (src/client/public — what Next serves at /) so previews
  resolve to real host URLs. Loaded via the same bundler-ignored dynamic
  import as the other built-in plugins; the dir is derived with string path
  ops on import.meta.url (not new URL(), which Turbopack tries to resolve as
  an asset). Added the matching public/ fixtures + dep + turbo build edge,
  and a dock-registration assertion in its test.

To keep the Next hub own booting test (and any short-lived host) from
leaving a background file watcher running, add a watch boolean option to
createAssetsDevframe (default true) and mount it with watch:false in the
Next hub. Vite hub keeps live-refresh on.

Co-authored-by: opencode <noreply@opencode.ai>

Author: antfubot

examples/next-devframe-hub/package.json

@@ -16,6 +16,7 @@
     "@devframes/json-render": "workspace:*",
     "@devframes/next": "workspace:*",
     "@devframes/plugin-a11y": "workspace:*",
+    "@devframes/plugin-assets": "workspace:*",
     "@devframes/plugin-code-server": "workspace:*",
     "@devframes/plugin-git": "workspace:*",
     "@devframes/plugin-inspect": "workspace:*",

examples/next-devframe-hub/src/client/devframe/next-devframe-hub.ts

@@ -4,6 +4,7 @@ import type { StartedServer } from 'devframe/node'
 import type { ConnectionMeta, DevframeDefinition } from 'devframe/types'
 import { homedir } from 'node:os'
 import process from 'node:process'
+import { fileURLToPath } from 'node:url'
 import { defineHubRpcFunction } from '@devframes/hub'
 import { createHubContext, mountDevframe } from '@devframes/hub/node'
 import { toJsonRenderDockEntry } from '@devframes/json-render/hub'
@@ -45,6 +46,24 @@ async function loadBuiltinPlugins(): Promise<DevframeDefinition[]> {
   return mods.map(mod => mod.default as DevframeDefinition)
 }
 
+/**
+ * Load the assets plugin and point its managed directory at this Next app's
+ * `public/` (`src/client/public`) — the exact directory Next serves at `/`,
+ * so the tab's previews resolve to real host URLs. Loaded through the same
+ * bundler-ignored dynamic `import()` as the other plugins (its node code and
+ * `import.meta.url`-based SPA-dist lookup don't survive static bundling), and
+ * mounted with `watch: false` so no background file watcher lingers when the
+ * hub is booted in a short-lived context (e.g. the example's own test).
+ */
+async function loadAssetsDevframe(): Promise<DevframeDefinition> {
+  const mod = await import(/* webpackIgnore: true */ /* turbopackIgnore: true */ '@devframes/plugin-assets')
+  // String path ops on the module path (not `new URL('../public', …)`, which
+  // Turbopack eagerly resolves as an asset import and fails on a directory) —
+  // `src/client/devframe/` → `src/client/public`, the dir Next serves at `/`.
+  const dir = join(dirname(fileURLToPath(import.meta.url)), '../public')
+  return (mod.createAssetsDevframe as (options: { dir: string, watch: boolean }) => DevframeDefinition)({ dir, watch: false })
+}
+
 /** URL base the a11y agent module is served under (same-origin, catch-all route). */
 const A11Y_AGENT_MOUNT_BASE = '/__df-a11y-agent/'
 
@@ -190,7 +209,7 @@ export async function nextDevframeHub(
 
   // Demo devframes alongside the dogfooded built-in plugin packages.
   const devframes = options.devframes
-    ?? [demoDevframe, demoDevframeB, ...await loadBuiltinPlugins()]
+    ?? [demoDevframe, demoDevframeB, ...await loadBuiltinPlugins(), await loadAssetsDevframe()]
 
   await context.messages.add({
     level: 'success',

examples/next-devframe-hub/src/client/public/data/notes.md

@@ -0,0 +1,6 @@
+# Next hub assets
+
+These files live in the Next app's `public/` directory (`src/client/public`),
+served by Next at the site root (`/`). The **Assets** dock is mounted with its
+`dir` pointed here, so previews load from Next's real URLs (`/logo.svg`,
+`/images/…`) and write actions round-trip to disk.

examples/next-devframe-hub/src/client/public/data/site.json

@@ -0,0 +1,12 @@
+{
+  "name": "Devframe Assets",
+  "description": "Sample fixtures for the assets plugin dev server.",
+  "theme": {
+    "primary": "#3a6a45",
+    "surface": "#ffffff"
+  },
+  "nav": [
+    { "label": "Home", "href": "/" },
+    { "label": "Docs", "href": "/docs" }
+  ]
+}

examples/next-devframe-hub/src/client/public/favicon.svg

@@ -0,0 +1,2 @@
+User-agent: *
+Allow: /