feat: Integrations splits into Library, Acquisition, Metadata sources and Email & network, each a page on the admin rail; the Overview keeps only what needs you (M503 #5607)

- Library: the folders, Run scan and a row per scan job, cover art, fingerprints and loudness (off the Overview and Duplicates)
- Acquisition: indexers and clients, searching, re-acquisition (off Missing files), Lidarr
- Metadata sources: AcoustID, and one provider block for cover art and tags in place of the pasted pair
- Email & network: outgoing email, the notification schedule, public address, proxies
- Lidarr, outgoing email and the provider block are rebuilt as SettingsGroup rows; failures read as sentences, not codes
- Duplicates and Missing files say what their setting is and link to where it is set

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/routes/collection/+layout.svelte

@@ -39,7 +39,7 @@
       getting for it, from user requests, new releases of the artists it follows, and albums whose
       files went missing. It searches your indexers on a schedule, checks each download against
       MusicBrainz, and files what's right into the library. Searching and quality are set under
-      <a href="/admin/integrations" class="text-accent-fg hover:underline">Integrations</a>.
+      <a href="/admin/acquisition" class="text-accent-fg hover:underline">Acquisition</a>.
     </p>
     {#if verdict}
       <p class="text-sm {needsYou ? 'text-text-primary' : 'text-text-secondary'}" data-testid="collection-verdict">