feat(player): PC 侧栏布局、顶栏与页内间距优化

- 桌面端侧栏 + 全局顶栏（Logo 在侧栏顶、激活态对齐后台红底白字）
- 移除各页重复页内顶栏，统一主区与卡片顶部留白
- 视口遮罩/弹层约束到主内容区，移动端保留底栏与顶栏 Logo

src/features/player/entry-gate.tsx

@@ -450,7 +450,7 @@ export function EntryGate() {
 
       <div className="flex flex-1 flex-col px-3 py-5">
         {phase === "loading" || waitingForEmbeddedToken ? (
-          <div className="mx-auto w-full max-w-md">
+          <div className="mx-auto w-full max-w-md lg:max-w-lg">
             <div className="mb-6 flex items-center gap-2">
               <div className="flex size-8 items-center justify-center rounded bg-red-600 text-white">
                 <Globe className="size-5" aria-hidden />
@@ -525,7 +525,7 @@ export function EntryGate() {
         ) : null}
 
         {phase === "failed" ? (
-          <div className="mx-auto w-full max-w-md">
+          <div className="mx-auto w-full max-w-md lg:max-w-lg">
             <div className="mb-6 text-center">
               <div className="mx-auto mb-4 flex size-16 items-center justify-center rounded-full bg-red-100 text-red-600">
                 <AlertTriangle className="size-8" aria-hidden />
@@ -601,7 +601,7 @@ export function EntryGate() {
         ) : null}
 
         {phase === "success" ? (
-          <div className="mx-auto w-full max-w-md text-center">
+          <div className="mx-auto w-full max-w-md text-center lg:max-w-lg">
             <div className="mb-6">
               <div className="mx-auto mb-4 flex size-16 items-center justify-center rounded-full bg-green-100 text-green-600">
                 <CheckCircle2 className="size-8" aria-hidden />

src/features/player/player-login-screen.tsx

@@ -160,7 +160,7 @@ export function PlayerLoginScreen(): React.ReactElement {
         </div>
       </div>
 
-      <div className="mx-auto w-full max-w-md flex-1 px-4 py-8">
+      <div className="mx-auto w-full max-w-md flex-1 px-4 py-8 lg:max-w-lg lg:px-8">
         <h1 className="text-xl font-bold text-gray-900">
           {t("login.title")}
         </h1>