fix: PC 端全站移动端响应式修复

Critical:
- header.tsx: 手机菜单按钮 flex-row→flex-col, 修复 w-full 溢出
- compare/page.tsx: 参数面板 grid-cols-3→grid-cols-1 sm:grid-cols-3

High:
- sandbox/page.tsx: header 区 flex-wrap + 模型选择器 w-48→w-40 sm:w-48
- member/page.tsx: 功能对比行 grid 布局替代 flex, 防溢出
- workshop/page.tsx: 编辑区 flex-col sm:flex-row + 按钮组 flex-wrap

Medium:
- analytics/page.tsx: domain name truncate
- skills/[id]: CTA 按钮 w-full sm:w-auto

frontend/src/app/my/member/page.tsx

@@ -118,10 +118,12 @@ export default function MemberPage() {
               </div>
               <div className="space-y-2 flex-1 mb-6">
                 {(plan.id === 'FREE' ? FEATURE_LABELS : FEATURE_LABELS).map((f, fi) => (
-                  <div key={f} className="flex items-center gap-2 text-sm">
-                    <span className="text-green-600 text-xs">✓</span>
-                    <span className="text-muted-foreground">{t.member[f]}</span>
-                    <span className="ml-auto text-xs text-foreground font-medium">{t.member[plan.features[fi]]}</span>
+                  <div key={f} className="grid grid-cols-[1fr_auto] gap-x-2 text-sm">
+                    <div className="flex items-center gap-2 min-w-0">
+                      <span className="text-green-600 text-xs shrink-0">✓</span>
+                      <span className="text-muted-foreground truncate">{t.member[f]}</span>
+                    </div>
+                    <span className="text-xs text-foreground font-medium text-right">{t.member[plan.features[fi]]}</span>
                   </div>
                 ))}
               </div>