perf(assets): Player/Admin 静态图改用 WebP，vs 保留 PNG

Player 端 banner/bg/card/h5bg 等改为 webp 并移除旧 png；Admin 登录背景改 webp；vs 对阵图仍用 png。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/player/src/views/ProfileView.vue

@@ -9,7 +9,7 @@ import { useAuthStore } from '../stores/auth';
 import { useAppLocale } from '../composables/useAppLocale';
 import GoldSpinner from '../components/GoldSpinner.vue';
 import { usePullToRefresh } from '../composables/usePullToRefresh';
-import walletBg from '../assets/images/wallet-bg.png';
+import walletBg from '../assets/images/wallet-bg.webp';
 
 const { t, locale } = useI18n();
 const router = useRouter();