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]>

css/tailwind.source.css

@@ -252,6 +252,34 @@
     display: block;
   }
 
+  /* Admin "verified" star — sits in the corner opposite the notification dot.
+     A gold star on a page-colored disc so it stays legible on any avatar, and
+     pairs visually with the red dot. Positioned top-left by default (the dot is
+     top-right); per-surface rules below tune the inset for larger avatars. */
+  .admin-star {
+    position: absolute;
+    top: 0;
+    left: 0;
+    z-index: 3;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    width: var(--space-sm);
+    height: var(--space-sm);
+    border-radius: var(--radius-full);
+    border: var(--border-width-hairline) solid var(--color-page);
+    background-color: var(--status-warning);
+    color: var(--color-warning-on);
+    font-size: var(--font-size-3xs);
+    line-height: 1;
+    pointer-events: none;
+  }
+
+  #profileButton .admin-star {
+    top: var(--space-2xs);
+    left: var(--space-2xs);
+  }
+
   .header-icon-toggle[data-theme-state="light"]:hover,
   .header-icon-toggle[data-theme-state="light"]:focus-visible {
     color: var(--color-text);
@@ -2706,6 +2734,7 @@
   }
 
   .comment-thread__avatar {
+    position: relative;
     inline-size: var(--comment-avatar-size);
     block-size: var(--comment-avatar-size);
   }
@@ -5731,6 +5760,14 @@
     font-size: var(--font-size-3xs);
   }
 
+  /* Non-clipped relative shell used only when a DM avatar needs an admin star
+     in its corner (the .dm-avatar itself clips to a circle). */
+  .dm-avatar-wrap {
+    position: relative;
+    display: inline-flex;
+    flex-shrink: 0;
+  }
+
   .dm-avatar {
     display: inline-flex;
     align-items: center;