perf: make mileage pagination explicit

src/modules/mileage/MonitoringView.tsx

@@ -492,6 +492,7 @@ export default function MonitoringView() {
   const [hasMore, setHasMore] = useState(true);
   const [loadingMore, setLoadingMore] = useState(false);
   const [pageLoading, setPageLoading] = useState(true);
+  const [pageError, setPageError] = useState<{ message: string; scope: 'first' | 'more' } | null>(null);
   const [manualRefreshing, setManualRefreshing] = useState(false);
   const [lastRefreshedAt, setLastRefreshedAt] = useState<Date | null>(null);
   const [showBackToTop, setShowBackToTop] = useState(false);
@@ -566,6 +567,7 @@ export default function MonitoringView() {
   // 加载首页数据
   const loadFirstPage = useCallback((showPageLoading = true) => {
     if (showPageLoading) setPageLoading(true);
+    setPageError(null);
     return fetchMonitoring({
       sortBy,
       sortOrder,
@@ -597,7 +599,12 @@ export default function MonitoringView() {
       setPage(1);
       setHasMore(d.page < d.totalPages);
       setLastRefreshedAt(new Date());
-    }).catch(() => {}).finally(() => {
+    }).catch(error => {
+      setPageError({
+        message: error instanceof Error ? error.message : '里程数据加载失败，请稍后重试',
+        scope: 'first',
+      });
+    }).finally(() => {
       if (showPageLoading) setPageLoading(false);
     });
   }, [sortBy, sortOrder, searchTerm, filterDept, filterCustomer, filterProject, filterEntity, filterRentStatus, filterPlatePrefix, filterTargetNames, filterRegion, filterPlates, appliedMileageRange, rangeStart, rangeEnd, filterBrands, sourcePriority]);
@@ -617,6 +624,7 @@ export default function MonitoringView() {
     if (loadingMore || !hasMore) return;
     const nextPage = page + 1;
     setLoadingMore(true);
+    setPageError(null);
     fetchMonitoring({
       sortBy,
       sortOrder,
@@ -642,7 +650,12 @@ export default function MonitoringView() {
       setVehicles(prev => [...prev, ...d.vehicles]);
       setPage(nextPage);
       setHasMore(nextPage < d.totalPages);
-    }).catch(() => {}).finally(() => setLoadingMore(false));
+    }).catch(error => {
+      setPageError({
+        message: error instanceof Error ? error.message : '更多车辆加载失败，请稍后重试',
+        scope: 'more',
+      });
+    }).finally(() => setLoadingMore(false));
   }, [sortBy, sortOrder, searchTerm, filterDept, filterCustomer, filterProject, filterEntity, filterRentStatus, filterPlatePrefix, filterTargetNames, filterRegion, filterPlates, appliedMileageRange, rangeStart, rangeEnd, page, loadingMore, hasMore, filterBrands, sourcePriority]);
 
   // 筛选/排序变化时重新加载
@@ -699,26 +712,6 @@ export default function MonitoringView() {
     return () => clearInterval(timer);
   }, [loadFirstPage]);
 
-  // 触底检测：用 IntersectionObserver 监听哨兵元素
-  const loadMoreRef = useRef(loadMore);
-  loadMoreRef.current = loadMore;
-  const sentinelRef = useRef<HTMLDivElement>(null);
-
-  useEffect(() => {
-    const sentinel = sentinelRef.current;
-    if (!sentinel) return;
-    const observer = new IntersectionObserver(
-      (entries) => {
-        if (entries[0].isIntersecting) {
-          loadMoreRef.current();
-        }
-      },
-      { rootMargin: '200px' }
-    );
-    observer.observe(sentinel);
-    return () => observer.disconnect();
-  }, []);
-
   // 回到顶部按钮：用 IntersectionObserver 检测顶部哨兵是否离开视口
   const topSentinelRef = useRef<HTMLDivElement>(null);
   useEffect(() => {
@@ -1500,7 +1493,9 @@ export default function MonitoringView() {
         </div>
         <div className="flex items-center justify-between px-1">
           <span className="text-[9px] font-black text-slate-400 uppercase tracking-widest">车辆详情清单</span>
-          <span className="text-[9px] font-bold text-slate-300">{total} 条</span>
+          <span className="text-[9px] font-bold text-slate-400">
+            已加载 {filteredVehicles.length} / 共 {total} 条
+          </span>
         </div>
         <div className="hidden grid-cols-[minmax(190px,1.1fr)_minmax(160px,1fr)_130px_130px] items-center gap-3 rounded-lg border border-slate-200 bg-white px-4 py-2 text-[10px] font-bold text-slate-400 md:grid">
           <span>车牌 / 数据状态</span>
@@ -1615,16 +1610,40 @@ export default function MonitoringView() {
           })}
         </div>
 
-        {filteredVehicles.length === 0 && !loadingMore && (
+        {filteredVehicles.length === 0 && !loadingMore && !pageError && (
           <div className="py-10 text-center bg-white rounded-2xl border border-dashed border-slate-100">
             <p className="text-xs font-bold text-slate-300">未找到匹配数据</p>
           </div>
         )}
 
-        {/* 加载更多提示 */}
-        {loadingMore && (
-          <div className="py-4 text-center">
-            <span className="text-[10px] font-bold text-slate-400">加载中...</span>
+        {pageError && (
+          <div className="rounded-xl border border-rose-100 bg-rose-50 px-3 py-3 text-center">
+            <p className="text-[10px] font-bold text-rose-600">{pageError.message}</p>
+            <button
+              type="button"
+              onClick={() => pageError.scope === 'more' ? loadMore() : loadFirstPage()}
+              disabled={pageLoading || loadingMore}
+              className="mt-2 inline-flex h-8 items-center gap-1.5 rounded-lg border border-rose-200 bg-white px-3 text-[10px] font-black text-rose-700 transition-colors hover:bg-rose-100 disabled:cursor-not-allowed disabled:opacity-60"
+            >
+              <RefreshCw size={12} className={pageLoading || loadingMore ? 'animate-spin' : ''} />
+              重试
+            </button>
+          </div>
+        )}
+        {hasMore && !pageError && filteredVehicles.length > 0 && (
+          <div className="flex flex-col items-center gap-1.5 py-4">
+            <button
+              type="button"
+              onClick={loadMore}
+              disabled={loadingMore}
+              className="inline-flex h-9 items-center gap-1.5 rounded-lg border border-slate-200 bg-white px-4 text-[11px] font-black text-slate-700 shadow-sm transition-colors hover:border-blue-200 hover:text-blue-600 disabled:cursor-not-allowed disabled:opacity-60"
+            >
+              {loadingMore ? <RefreshCw size={13} className="animate-spin" /> : <ChevronDown size={14} />}
+              {loadingMore ? '加载中' : '加载更多'}
+            </button>
+            <span className="text-[9px] font-bold text-slate-300">
+              已加载 {filteredVehicles.length} / 共 {total} 条
+            </span>
           </div>
         )}
         {!hasMore && filteredVehicles.length > 0 && (
@@ -1632,8 +1651,6 @@ export default function MonitoringView() {
             <span className="text-[10px] font-bold text-slate-300">已加载全部 {total} 条</span>
           </div>
         )}
-        {/* 哨兵元素：进入视口时触发加载更多 */}
-        <div ref={sentinelRef} className="h-1" />
       </div>
 
       <VehicleDetailModal