stage-34 wire admin nav: federation hub links to discovery + SW v4

src/psyc/cockpit/static/sw.js

@@ -5,7 +5,7 @@
 // This makes the cockpit installable as a PWA and survives flaky connections,
 // without serving stale operational data behind the operator's back.
 
-const CACHE_VERSION = "psyc-v3";
+const CACHE_VERSION = "psyc-v4";
 const STATIC_ASSETS = [
   "/static/cockpit.css",
   "/static/psyc-tokens.css",

src/psyc/cockpit/templates/admin_federation.html

@@ -8,7 +8,7 @@
     <span class="count">{{ peers|length }} peer{{ '' if peers|length == 1 else 's' }}</span>
   </div>
   <p class="page-intro">This node's Ed25519 identity. The fingerprint goes into a DNS TXT record so other psyc nodes can discover this one. The public key lets them verify any feed we publish — the private key never leaves this box.</p>
-  <p class="back"><a href="/admin">← back to admin</a> &nbsp;·&nbsp; <a href="/admin/federation/vouches">vouches</a> &nbsp;·&nbsp; <a href="/admin/federation/quorum">quorum config</a> &nbsp;·&nbsp; <a href="/admin/federation/log">transparency log</a></p>
+  <p class="back"><a href="/admin">← back to admin</a> &nbsp;·&nbsp; <a href="/admin/federation/discovery">discovery</a> &nbsp;·&nbsp; <a href="/admin/federation/vouches">vouches</a> &nbsp;·&nbsp; <a href="/admin/federation/quorum">quorum config</a> &nbsp;·&nbsp; <a href="/admin/federation/log">transparency log</a></p>
 
   <div class="card" style="margin-bottom:14px;">
     <div class="lg-sub">node fingerprint</div>