fix(discord): non-owners no longer see a stuck "Loading…" on the servers card (#213)

The card only loads for owners/admins (the list endpoint is owner-only), so a
member saw "Loading…" forever. Show an owner-only note instead. Also assert the
one-server/two-org race really retried, as the PR body already claimed.

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

drb-frontend/components/DiscordServersCard.tsx

@@ -171,7 +171,10 @@ export function DiscordServersCard({ canEdit, isAdmin }: { canEdit: boolean; isA
             </tr>
           </thead>
           <tbody>
-            {guilds === null && !loadError && (
+            {!canEdit && (
+              <tr><td colSpan={4} className="px-5 py-4 text-xs text-ink-muted">Only the organization owner can see and link Discord servers.</td></tr>
+            )}
+            {canEdit && guilds === null && !loadError && (
               <tr><td colSpan={4} className="px-5 py-4 text-xs text-ink-muted">Loading…</td></tr>
             )}
             {loadError && (