web-ui: shrink KPI card height on home dashboard

Reduce vertical padding, number font size, and inter-element gaps so
the four counters take less vertical real estate. Width unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web-ui/src/components/cases/kpi-cards.tsx

@@ -49,14 +49,14 @@ export function KPICards({ cases, loading }: { cases?: Case[]; loading?: boolean
             ${TONE_STYLES[b.tone]}
           `}
         >
-          <CardContent className="px-5 py-4 flex flex-col gap-1">
+          <CardContent className="px-5 py-3 flex flex-col gap-0.5">
             <span className="text-[0.72rem] uppercase tracking-[0.08em] text-ink-muted">
               {b.label}
             </span>
-            <span className="font-display text-[2.3rem] font-black leading-none">
+            <span className="font-display text-[1.7rem] font-black leading-none">
               {loading ? "—" : b.value}
             </span>
-            <span className="text-[0.78rem] text-ink-muted mt-0.5">{b.caption}</span>
+            <span className="text-[0.74rem] text-ink-muted">{b.caption}</span>
           </CardContent>
         </Card>
       ))}