fix(search): AIUI web search was 403ing on every query

SearXNG defaults to `formats: [html]`. Its JSON API answers 403 —
and JSON is the only thing AIUI's web search speaks, since
`/aiui/api/web-search` proxies straight through to `/search`. Both
places that seed settings.yml (the first-boot script and the installer)
omitted `search.formats`, so web search has never worked on a node
whose SearXNG was installed, running and healthy. It reads as the
assistant being unable to search rather than as one missing config key.

Verified on archi-dev-box: `format=json` went 403 -> 200, returning 28
results for "bitcoin halving" from Brave and DuckDuckGo. Google and
Startpage self-suspend on a self-hosted instance (access denied /
CAPTCHA), which is expected and costs little given Brave's independent
index.

Existing nodes need the same two lines added to
/var/lib/archipelago/searxng/settings.yml and a restart; this commit
only fixes what new installs get.

Also fixes a build break: `fetchLibraryContent` built a bundle literal
that predates the images bucket.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

neode-ui/src/services/contextBroker.ts

@@ -538,7 +538,7 @@ export class ContextBroker {
         method: 'music.list-tracks',
         params: { limit: 500 },
       })
-      return { films: [], songs: adaptLibraryTracks(res.tracks ?? []), podcasts: [] }
+      return { ...emptyBundle(), songs: adaptLibraryTracks(res.tracks ?? []) }
     } catch {
       return emptyBundle()
     }