fix(操作统计): 全不选生效——默认全选，全不选后显示空态提示

- 打开抽屉默认全选所有人(宫格高亮+显示全部)
- 点「全不选」清空选择，表格显示『未选择任何人员』空态，不再退化为全部
- 首次加载自动全选；用户操作过筛选后不覆盖

frontend/src/pages/admin/AdminDashboard.tsx

@@ -274,7 +274,8 @@ export default function AdminDashboard() {
   const [opsDrawerOpen, setOpsDrawerOpen] = useState(false);
   const [opStats, setOpStats] = useState<UserOperation[]>([]);
   const [opLoading, setOpLoading] = useState(false);
-  const [opFilterUsers, setOpFilterUsers] = useState<Set<string>>(new Set()); // 多选人员，空 = 全部
+  const [opFilterUsers, setOpFilterUsers] = useState<Set<string>>(new Set()); // 多选人员
+  const [opFilterTouched, setOpFilterTouched] = useState(false); // 用户是否主动操作过筛选
   const [opSort, setOpSort] = useState<{ key: string; order: "asc" | "desc" } | null>(null);
   // 操作明细下钻
   const [opDetailOpen, setOpDetailOpen] = useState(false);
@@ -349,12 +350,21 @@ export default function AdminDashboard() {
   const openOpsDrawer = () => {
     setOpsDrawerOpen(true);
     setOpFilterUsers(new Set());
+    setOpFilterTouched(false);
     setOpSort(null);
     loadUserOperations();
   };
 
+  // 首次加载完成后默认全选（显示全部）；用户操作过筛选后不再自动覆盖
+  useEffect(() => {
+    if (!opFilterTouched && opStats.length > 0) {
+      setOpFilterUsers(new Set(opStats.map(u => u.user_id)));
+    }
+  }, [opStats, opFilterTouched]);
+
   // 人员多选切换
   const toggleOpFilterUser = (id: string) => {
+    setOpFilterTouched(true);
     setOpFilterUsers(prev => {
       const next = new Set(prev);
       if (next.has(id)) next.delete(id); else next.add(id);
@@ -362,8 +372,14 @@ export default function AdminDashboard() {
     });
   };
   // 全选 / 全不选
-  const selectAllUsers = () => setOpFilterUsers(new Set(opStats.map(u => u.user_id)));
-  const clearAllUsers = () => setOpFilterUsers(new Set());
+  const selectAllUsers = () => {
+    setOpFilterTouched(true);
+    setOpFilterUsers(new Set(opStats.map(u => u.user_id)));
+  };
+  const clearAllUsers = () => {
+    setOpFilterTouched(true);
+    setOpFilterUsers(new Set());
+  };
 
   // 表头升降序：无 → 升序 → 降序 → 无
   const toggleOpSort = (key: string) => {
@@ -758,10 +774,12 @@ export default function AdminDashboard() {
           </div>
         ) : opStats.length === 0 ? (
           <div className="py-16 text-center text-sm text-gray-400">该时段暂无操作记录</div>
+        ) : opFilterUsers.size === 0 ? (
+          <div className="py-16 text-center text-sm text-gray-400">未选择任何人员，请点击「全选」或选择人员</div>
         ) : (
           (() => {
             // 过滤 + 排序后的数据
-            let list = opFilterUsers.size > 0 ? opStats.filter(u => opFilterUsers.has(u.user_id)) : opStats;
+            let list = opStats.filter(u => opFilterUsers.has(u.user_id));
             if (opSort) {
               const key = opSort.key;
               const getVal = (u: UserOperation) => key === "receive" ? u.receive_count : key === "transfer" ? u.transfer_count : key === "record" ? u.record_count : u.total;