Admin star badge on admin avatars across the app

Show a small gold "verified admin" star in the corner opposite the red
notification dot whenever a rendered profile belongs to a bitvid admin
(the super admin or a current list editor).

- adminBadge.js (new): isAdminActor(hex|npub) sync check against
  accessControl, and applyAdminStar(container, id) which adds/removes a
  single `.admin-star` in a non-clipped, positioned container. Idempotent.
- CSS: `.admin-star` (top-left gold disc, mirrors the top-right dot),
  `.dm-avatar-wrap`, and position:relative on the comment avatar wrapper.
- Profile button: app.refreshAdminStar() lights the logged-in user's star;
  re-runs on login/logout and on accessControl.onEditorsChange (so a
  late-loading editor list still resolves).
- Comments: star on comment-author avatars (commentNodeFactory).
- Channel page: wrap the clipped avatar and star the channel owner.
- DMs: Avatar gains an opt-in adminId — only admin avatars get wrapped so
  non-admin rows are byte-identical; ContactRow passes the peer pubkey.
- tests: admin-badge unit coverage (recognition, idempotency, removal).

Co-Authored-By: Claude Opus 4.8 <[email protected]>

views/channel-profile.html

@@ -23,16 +23,18 @@
           aria-live="polite"
         ></div>
         <div class="flex items-center">
-          <div
-            class="h-16 w-16 overflow-hidden rounded-full border-2 border-border-translucent-bright max-sm:h-12 max-sm:w-12"
-          >
-            <img
-              id="channelAvatar"
-            src="assets/svg/default-profile.svg"
-            alt="Avatar"
-            class="h-full w-full object-cover"
-          />
-        </div>
+          <div id="channelAvatarWrap" class="relative">
+            <div
+              class="h-16 w-16 overflow-hidden rounded-full border-2 border-border-translucent-bright max-sm:h-12 max-sm:w-12"
+            >
+              <img
+                id="channelAvatar"
+                src="assets/svg/default-profile.svg"
+                alt="Avatar"
+                class="h-full w-full object-cover"
+              />
+            </div>
+          </div>
           <div class="ml-4 text-text">
             <h2 id="channelName" class="text-xl font-bold max-sm:text-base">User Name</h2>
             <p id="channelNpub" class="text-sm opacity-80 max-sm:text-2xs">npub...</p>