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/app/(dashboard)/messages/page.tsx

@@ -1,3 +1,4 @@
+import { PageTransition } from "@/components/shared";
 import { getConfig, getGuilds } from "@/lib/api/server";
 import { MessagesView } from "./view";
 
@@ -12,9 +13,11 @@ export default async function MessagesPage() {
     /* client hooks surface errors */
   }
   return (
-    <MessagesView
-      initialGuilds={guilds}
-      initialGuildId={config?.monitorGuildId ?? null}
-    />
+    <PageTransition>
+      <MessagesView
+        initialGuilds={guilds}
+        initialGuildId={config?.monitorGuildId ?? null}
+      />
+    </PageTransition>
   );
 }