added api logic, vitest, minimal testing ui

web/src/components/Skeleton.tsx

@@ -0,0 +1,19 @@
+export function Skeleton({ className = "" }: { className?: string }) {
+  return <div className={`animate-pulse rounded-[--radius-xl] bg-[color-mix(in_oklab,var(--color-ink) 70%,transparent)] ${className}`} />;
+}
+export function KPISkeleton() {
+  return <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-3">
+    <Skeleton className="h-24" />
+    <Skeleton className="h-24" />
+    <Skeleton className="h-24" />
+  </div>;
+}
+export function ChartSkeleton({ tall=false }: { tall?: boolean }) {
+  return <Skeleton className={tall ? "h-80" : "h-64"} />;
+}
+export function TableSkeleton() {
+  return <div className="card">
+    <div className="section-title">Loading…</div>
+    <Skeleton className="h-40" />
+  </div>;
+}