Remove the RepoISO integration; keep generic support for shares of other services

RepoISO now manages the NAS itself, so nasmon no longer polls it (settings field, dashboard card,
menu link and repoiso:* alerts are gone). Drop-in SMB includes, read-only listing and keeping
smbd/nfs-server running for other software's shares stay.

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

internal/web/templates/dashboard.html

@@ -104,26 +104,6 @@
   </table></div>
 </section>
 
-{{with .S.RepoISO}}
-<section class="card" id="repoiso">
-  <h2>RepoISO {{if $.RepoISO}}<a class="muted small" href="{{$.RepoISO}}" target="_blank" rel="noopener">open ↗</a>{{end}}
-    {{if not .Reachable}}<span class="badge crit">not responding</span>
-    {{else if not .WorkerAlive}}<span class="badge warn">worker stopped</span>
-    {{else}}<span class="badge ok">running</span>{{end}}
-    {{if .Version}}<span class="muted small">v{{.Version}}</span>{{end}}</h2>
-  {{if not .Reachable}}<div class="flash crit">{{.URL}}/api/integration/status: {{.Error}}</div>{{else}}
-  <div class="tablewrap"><table class="compact">
-    <tbody>
-      <tr><td class="muted">Images</td><td class="num">{{.Images}}</td><td>{{bytes .ImagesBytes}}{{if .ImagesPending}} · <span class="muted">{{.ImagesPending}} being checked</span>{{end}}{{if .ImagesError}} · <span class="crit">{{.ImagesError}} with errors</span>{{end}}</td></tr>
-      <tr><td class="muted">Publications</td><td class="num">{{.Publications}}</td><td>{{if .PublicationsError}}<span class="badge warn">{{.PublicationsError}} not mounted</span>{{else}}<span class="muted">HTTP repositories / file trees</span>{{end}}</td></tr>
-      <tr><td class="muted">Jobs</td><td class="num">{{.JobsActive}}</td><td>{{if .JobsActive}}active{{else}}<span class="muted">idle</span>{{end}}{{if .JobsFailed24h}} · <span class="badge warn">{{.JobsFailed24h}} failed in 24 h</span>{{end}}</td></tr>
-      <tr><td class="muted">Proxmox exports</td><td class="num">{{.Exports}}</td><td class="muted">NFS / SMB shares — listed on <a href="/shares#external">Shares</a></td></tr>
-      <tr><td class="muted">Worker</td><td></td><td class="small">{{if .WorkerHeartbeat}}last heartbeat {{.WorkerHeartbeat}}{{else}}no heartbeat yet{{end}}</td></tr>
-    </tbody>
-  </table></div>{{end}}
-</section>
-{{end}}
-
 <section class="card">
   <h2>Datasets</h2>
   <div class="tablewrap"><table>