Remove internal nav reference from sidebar comment

Co-Authored-By: Paperclip <noreply@paperclip.ing>

ui/src/components/Sidebar.tsx

@@ -57,7 +57,7 @@ export function Sidebar() {
   });
   const liveRunCount = liveRuns?.length ?? 0;
   const showWorkspacesLink = experimentalSettings?.enableIsolatedWorkspaces === true;
-  // IA flag (PAP-89): branch the sidebar nav presentation. Default ON =
+  // IA flag: branch the sidebar nav presentation. Default ON =
   // streamlined (top-level Projects link). Users can opt out in experiments to
   // get classic (per-project collapsible, no Projects nav link). Issue/Task
   // wording is split to PR #7651. Gating is navigation-only; all routes stay