Revert skill list layout and tune leaderboard report

- Revert skill settings to vertical list layout with pinned sorting
- Default leaderboard range 30d -> 7d, hide stats while report generating
- Reframe leaderboard report prompt as user-behavior analysis (cache v5)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend-web/src/pages/AdminUserLeaderboardPage.tsx

@@ -100,7 +100,7 @@ function toDateInput(date: Date): string {
   return `${year}-${month}-${day}`;
 }
 
-function defaultRange(days = 30): RangeState {
+function defaultRange(days = 7): RangeState {
   const end = new Date();
   const start = new Date();
   start.setDate(end.getDate() - days + 1);
@@ -108,7 +108,7 @@ function defaultRange(days = 30): RangeState {
 }
 
 function rangeForApi(range: RangeState) {
-  const normalized = range.since && range.until ? range : defaultRange(30);
+  const normalized = range.since && range.until ? range : defaultRange(7);
   const start = new Date(`${normalized.since}T00:00:00`);
   const end = new Date(`${normalized.until}T23:59:59`);
   return {
@@ -1035,7 +1035,7 @@ function UserDetailPanel({
 
 export default function AdminUserLeaderboardPage() {
   const navigate = useNavigate();
-  const [range, setRange] = useState<RangeState>(() => defaultRange(30));
+  const [range, setRange] = useState<RangeState>(() => defaultRange(7));
   const [tab, setTab] = useState<UserRankTab>("activity");
   const [query, setQuery] = useState("");
   const [groupRules, setGroupRules] = useState("zero,two");
@@ -1288,7 +1288,7 @@ export default function AdminUserLeaderboardPage() {
                       {reportGenerating ? "生成中" : "生成报告"}
                     </Button>
                   </div>
-                  {data && (
+                  {data && reportStatus === "idle" && !reportText && (
                     <div className="mx-6 mt-4 grid shrink-0 gap-3 md:grid-cols-3">
                       <section className="rounded-lg border border-[#F1D6D6] bg-white p-3 dark:border-[#462123] dark:bg-[#230D0F]">
                         <div className="mb-2 flex items-center gap-2 text-sm font-semibold text-[#231815] dark:text-white">