fix(dashboard): match the tile skeleton to the resting tile height

The tile-strip skeleton and per-tile Suspense fallback reserved only 6rem,
shorter than a populated TrendCard (~8rem), so the strip grew when data
landed. Bump both to 8rem and mirror the card's overflow-hidden chrome on
the fallback to keep first-paint layout shift at zero.

src/app/page.tsx

@@ -1599,7 +1599,7 @@ export default function DashboardPage() {
                 {Array.from({ length: configuredTileCount }).map((_, idx) => (
                   <div
                     key={`tile-skeleton-${idx}`}
-                    className="bg-card border-border min-h-[6rem] animate-pulse rounded-xl border p-4 motion-reduce:animate-none md:p-6"
+                    className="bg-card border-border min-h-[8rem] animate-pulse rounded-xl border p-4 motion-reduce:animate-none md:p-6"
                   />
                 ))}
               </div>
@@ -1660,7 +1660,7 @@ export default function DashboardPage() {
                       fallback={
                         <div
                           aria-hidden="true"
-                          className="bg-card border-border flex h-full min-h-[6rem] w-full min-w-0 flex-col rounded-xl border p-4 md:p-6"
+                          className="bg-card border-border flex h-full min-h-[8rem] w-full min-w-0 flex-col overflow-hidden rounded-xl border p-4 md:p-6"
                         />
                       }
                     >