feat: add ticket workflow pages

frontend/src/components/app/AppEmptyState.tsx

@@ -0,0 +1,13 @@
+type AppEmptyStateProps = {
+  title: string
+  description?: string
+}
+
+export function AppEmptyState({ title, description }: AppEmptyStateProps) {
+  return (
+    <div className="rounded-lg border border-dashed border-border bg-surface px-4 py-8 text-center">
+      <p className="text-sm font-medium text-foreground">{title}</p>
+      {description ? <p className="mt-1 text-sm text-muted-foreground">{description}</p> : null}
+    </div>
+  )
+}