fix: consolidate DagTask types, fix REST fallback shape, fix lint noqa

- Extract shared DagTask/DagTaskStatus types into www/app/lib/dagTypes.ts
- Re-export from useWebSockets.ts and UserEventsProvider.tsx
- Fix browse page REST fallback: dag_status is list[dict] directly, not {tasks: [...]}
- Add missing # noqa: PLC0415 for fork-safe deferred imports

www/app/(app)/browse/_components/TranscriptCards.tsx

@@ -145,11 +145,9 @@ function TranscriptCard({
             status={result.status}
             dagStatus={
               dagStatusMap?.get(result.id) ??
-              (
-                (result as Record<string, unknown>).dag_status as
-                  | { tasks?: DagTask[] }
-                  | undefined
-              )?.tasks ??
+              ((result as Record<string, unknown>).dag_status as
+                | DagTask[]
+                | null) ??
               null
             }
           />