feat(卡点分析): 后台卡点分析按知识点 → 题 → 一道题重做，年度趋势改名历年概况只留逐学年总表

- 选班后只列这个班课上布置过的题，右栏换成「交了几次才对」和交得最多的人
- 历年概况可以导出表格；旧地址 top_ac_trend 跳到新页面

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/shared/layout/admin.vue

@@ -85,9 +85,9 @@ const NAV: NavGroup[] = [
         role: "teacher",
       },
       {
-        label: "年度趋势",
+        label: "历年概况",
         icon: "ph:chart-line-up",
-        path: "/admin/problem/top_ac_trend",
+        path: "/admin/problem/yearly",
         role: "teacher",
       },
       { label: "自学情况", icon: "ph:student", path: "/admin/learn", role: "teacher" },