feat(frontend): micro-interactions — page-enter transition + MetricTile lift

- Add animate-fade-up utility (reduced-motion aware) and a PageTransition
  wrapper; every dashboard view now rises + settles on mount/route change.
- MetricTile gains a subtle hover lift (-translate-y) + ring-focus glow.
- Theme toggle and command palette (⌘K) already existed and persist; no-op.

services/frontend/src/components/shared/page-transition.tsx

@@ -0,0 +1,15 @@
+import { cn } from "@/lib/utils";
+
+/**
+ * Wraps a view's root so the whole panel stack rises + settles on mount.
+ * The animation is disabled under prefers-reduced-motion via globals.css.
+ */
+export function PageTransition({
+  children,
+  className,
+}: {
+  children: React.ReactNode;
+  className?: string;
+}) {
+  return <div className={cn("animate-fade-up", className)}>{children}</div>;
+}