fix(12-07): make ['me'] fresh on shell entry so post-wizard banner clears (gap 6)

- Root cause confirmed = mechanism (ii): ['me'] staleness, NOT a backend linking gap
  (upsertUser claim preserves users.id → credential stays linked → DB needsProviderSetup=false)
- SetupBanner ['me'] query staleTime 5min → 0 so a pre-claim stale cache entry is
  refetched on mount; banner hides once needsProviderSetup resolves false
- App.tsx boot ['me'] staleTime also set to 0 (committed with Task 1) for the same reason
- Add SetupBanner.test.tsx regression: absent when false, present (no dismiss) when true,
  stale-cache refetch hides banner; success-only dismissal contract preserved (no X button)
- Log pre-existing PWA lint errors (SetupPage.test.tsx, setupClient.contract.test.ts) to deferred-items.md

apps/pwa/src/components/SetupBanner.tsx

@@ -33,11 +33,18 @@ export function SetupBanner() {
   // Use HTMLButtonElement for the ref (assignable to the CredentialSheet's HTMLElement trigger)
   const ctaRef = useRef<HTMLButtonElement>(null);
 
+  // staleTime 0 (gap 6): this banner gates on needsProviderSetup, which is only
+  // correct if ['me'] is fresh on entry to the authenticated shell after the
+  // wizard claim (see App.tsx for the full mechanism note). With a 5-minute
+  // staleTime a pre-claim cache entry kept needsProviderSetup=true and the banner
+  // showed even though the operator already configured the calendar in the wizard.
+  // The success-only dismissal contract is unchanged: this banner still clears
+  // ONLY when needsProviderSetup becomes false (no dismiss/X button).
   const meQuery = useQuery({
     queryKey: ['me'],
     queryFn: fetchMe,
     retry: false,
-    staleTime: 5 * 60 * 1000,
+    staleTime: 0,
   });
 
   // Only show when needsProviderSetup is explicitly true