perf: Remove preview polling in favour of SSE-driven invalidation

refetchInterval: 3000 on listPreviews and getPreviewStatus is now
redundant. Phase oMHtTekCDgdnBG0kkk25A wired useLiveUpdates in
$id.tsx to invalidate both queries on every preview:* SSE event,
so queries refetch exactly once per state change instead of on
a fixed 3-second timer.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/src/components/review/ReviewTab.tsx

@@ -80,7 +80,6 @@ export function ReviewTab({ initiativeId }: ReviewTabProps) {
   // Preview state
   const previewsQuery = trpc.listPreviews.useQuery(
     { initiativeId },
-    { refetchInterval: 3000 },
   );
   const existingPreview = previewsQuery.data?.find(
     (p) => p.phaseId === activePhaseId || p.initiativeId === initiativeId,
@@ -90,7 +89,6 @@ export function ReviewTab({ initiativeId }: ReviewTabProps) {
     { previewId: activePreviewId ?? existingPreview?.id ?? "" },
     {
       enabled: !!(activePreviewId ?? existingPreview?.id),
-      refetchInterval: 3000,
     },
   );
   const preview = previewStatusQuery.data ?? existingPreview;