fix: refresh latest regime trading session

frontend/src/pages/RegimePage.tsx

@@ -328,6 +328,12 @@ export default function RegimePage() {
               footnote={<>Breadth divergence, SMH/SPY rollover, and point-in-time fundamental observations. Unknown or stale fundamentals reduce coverage; they never default to 50.</>}
             />
           </div>
+          <p className="text-xs text-gray-600">
+            Data quality · oldest market input:{' '}
+            {data.data_quality?.oldest_market_input_age_days == null
+              ? 'unavailable'
+              : `${data.data_quality.oldest_market_input_age_days}d`}
+          </p>
 
           <Suspense fallback={<SkeletonCard className="h-80" />}><RegimeQuadrant /></Suspense>
           <Suspense fallback={<SkeletonCard className="h-72" />}><ScoreHistoryChart /></Suspense>