fix: 车辆详情清单标题也吸顶，与KPI合为一个sticky块

Tab栏 + KPI统计 + 清单标题 三层吸顶：
- Tab栏 sticky top-0
- KPI + 清单标题 sticky top-[44px]
移动端和Web端都生效。

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/modules/mileage/MonitoringView.tsx

@@ -708,12 +708,10 @@ export default function MonitoringView() {
         );
       })()}
 
-      {/* High Density KPI Grid — sticky below tab bar */}
+      {/* Sticky header: KPI + 清单标题 */}
-      <div className="sticky top-[44px] z-20 bg-[#F8F9FB] py-1">
+      <div className="sticky top-[44px] z-20 bg-[#F8F9FB] pt-1 pb-1 space-y-2">
         <div className="grid grid-cols-4 gap-2">
           <div className="col-span-2 bg-slate-900 p-2.5 rounded-xl text-white relative overflow-hidden">
-            <div className="flex items-baseline justify-between">
-              <div>
             <div className="text-[7px] font-bold text-slate-500 uppercase tracking-wider">{sortBy === 'today' ? '今日' : '累计'}总里程</div>
             <div className="text-lg font-black tracking-tighter leading-tight flex items-baseline gap-1">
               {Math.round(sortBy === 'today' ? stats.totalToday : stats.totalAll).toLocaleString()}
@@ -725,8 +723,6 @@ export default function MonitoringView() {
               })()}
             </div>
           </div>
-            </div>
-          </div>
           <div className="bg-white p-2.5 rounded-xl border border-gray-100 shadow-sm">
             <div className="text-[7px] font-bold text-slate-400 uppercase">平均单车</div>
             <div className="text-sm font-black text-slate-800 leading-tight">{(stats.vehicleCount > 0 ? (sortBy === 'today' ? stats.totalToday : stats.totalAll) / stats.vehicleCount : 0).toFixed(0)}</div>
@@ -738,14 +734,14 @@ export default function MonitoringView() {
             <div className="text-[7px] text-slate-400">台</div>
           </div>
         </div>
-      </div>
+        <div className="flex items-center justify-between px-2">
-
-      {/* High-Density Vehicle List - Two Columns on Tablet, One on Mobile */}
-      <div className="space-y-1.5">
-        <div className="flex items-center justify-between px-2 mb-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>
         </div>
+      </div>
+
+      {/* Vehicle List */}
+      <div className="space-y-1.5">
 
         <div className="grid grid-cols-1 gap-1.5">
           {filteredVehicles.map((v) => (