Add Today dashboard foundation with permission-aware KPI summary API.

Replace hardcoded Today cards with a backend summary endpoint and composable frontend widgets filtered by org type and tab permissions.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/components/today/TodayKpiGrid.tsx

@@ -0,0 +1,51 @@
+'use client';
+
+import { useTranslations } from 'next-intl';
+import { useAuth } from '@/lib/hooks/useAuth';
+import { KpiCard } from '@/components/today/KpiCard';
+import { getEligibleTodayKpis, getVisibleTodayKpis } from '@/components/today/widget-registry';
+import type { TodaySummaryWidgets } from '@/types/today';
+
+interface TodayKpiGridProps {
+  widgets: TodaySummaryWidgets;
+  loading?: boolean;
+}
+
+export function TodayKpiGrid({ widgets, loading = false }: TodayKpiGridProps) {
+  const t = useTranslations('today');
+  const { currentOrganization } = useAuth();
+  const definitions = loading
+    ? getEligibleTodayKpis(currentOrganization)
+    : getVisibleTodayKpis(currentOrganization, widgets);
+
+  if (!loading && definitions.length === 0) {
+    return (
+      <p className="text-sm text-text-muted">{t('noWidgets')}</p>
+    );
+  }
+
+  return (
+    <div className="grid grid-cols-1 md:grid-cols-2 xl:grid-cols-4 gap-4">
+      {definitions.map((definition) => {
+        const value = definition.formatValue(widgets) ?? '—';
+        const subtitleKey = definition.formatSubtitle?.(widgets);
+        const subtitle =
+          subtitleKey === 'unlimited'
+            ? t('seatsUnlimited')
+            : definition.formatSubtitle?.(widgets);
+
+        return (
+          <KpiCard
+            key={definition.key}
+            title={t(definition.titleKey)}
+            value={value}
+            subtitle={subtitle}
+            icon={definition.icon}
+            color={definition.color}
+            loading={loading}
+          />
+        );
+      })}
+    </div>
+  );
+}