feat(ui): modern shadcn/ui theme with violet accent across all pages

Add shadcn/ui (Radix + Tailwind 4) components, zinc/violet theme tokens and self-hosted Inter. New header with user menu, Steam cover art, skeletons and toasts. Replace @mdi/font with lucide-react. Fix: top-owned list on the landing page only showed with top-played entries; numbers use the app language.

jsconfig.json

@@ -0,0 +1,8 @@
+{
+  "compilerOptions": {
+    "baseUrl": ".",
+    "paths": {
+      "@/*": ["./src/*"]
+    }
+  }
+}