fix(ux): apply UX quick wins (#54)

Get started links to registration and says an admin approves accounts.
Back navigation restores the library scroll; search no longer fills history.
Steam and PSN unlink ask first. Any close marks news as seen.
Confetti plays only when the level rises on the page.
Count-ups respect reduced motion. Html lang follows the UI language.
Add a 404 page, translated role and dialog close label.

src/components/StatCard.jsx

@@ -2,14 +2,15 @@ import {useEffect, useState} from 'react';
 import {useTranslation} from 'react-i18next';
 
 import {Card} from '@/components/ui/card';
+import useReducedMotion from '../hooks/useReducedMotion.js';
 import {useDrillTarget} from './stats/StatDrill.jsx';
 
-function useCountUp(target, durationMs = 1600) {
+function useCountUp(target, instant, durationMs = 1600) {
     const [value, setValue] = useState(0);
     useEffect(() => {
         const safeTarget = typeof target === 'number' && Number.isFinite(target) ? target : 0;
-        if (safeTarget === 0) {
-            setValue(0);
+        if (instant || safeTarget === 0) {
+            setValue(safeTarget);
             return;
         }
         let raf;
@@ -22,7 +23,7 @@ function useCountUp(target, durationMs = 1600) {
         };
         raf = requestAnimationFrame(step);
         return () => cancelAnimationFrame(raf);
-    }, [target, durationMs]);
+    }, [target, instant, durationMs]);
     return value;
 }
 
@@ -32,7 +33,8 @@ function useCountUp(target, durationMs = 1600) {
  */
 export default function StatCard({label, value, icon: Icon, suffix, drill, onClick}) {
     const {i18n} = useTranslation();
-    const animated = useCountUp(value);
+    const reduce = useReducedMotion();
+    const animated = useCountUp(value, reduce);
     const target = useDrillTarget({title: label, count: value, ...drill}) ?? (onClick && {onClick});
     const card = (
         <Card className="gap-3 p-5">