feat: 客户筛选部门和业务负责人联动

- 选择部门后，业务负责人下拉只显示该部门的人
- 切换部门时自动清空已选的业务负责人
- 未选部门时显示所有部门的负责人

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

src/App.tsx

@@ -2289,7 +2289,10 @@ export default function App() {
                           <label className="text-[10px] font-bold text-gray-400 uppercase tracking-wider">业务负责人</label>
                           <select className="w-full bg-white border border-gray-200 rounded-lg py-2 px-2 text-xs focus:ring-2 focus:ring-emerald-500/20 focus:border-emerald-500 outline-none transition-all cursor-pointer shadow-sm" value={draftCustomerFilters.manager} onChange={(e) => setDraftCustomerFilters(prev => ({ ...prev, manager: e.target.value }))}>
                             <option value="">所有负责人</option>
-                            {customerManagersGroupedByDept.filter(g => g.department !== '公务车').map(g => (
+                            {customerManagersGroupedByDept
+                              .filter(g => g.department !== '公务车')
+                              .filter(g => !draftCustomerFilters.department || g.department === draftCustomerFilters.department)
+                              .map(g => (
                               <optgroup key={g.department} label={g.department}>
                                 {g.managers.map(m => <option key={m} value={m}>{m}</option>)}
                               </optgroup>
@@ -2307,7 +2310,7 @@ export default function App() {
                           </div>
                           <div className="space-y-1.5">
                             <label className="text-[10px] font-bold text-gray-400 uppercase tracking-wider">部门</label>
-                            <select className="w-full bg-white border border-gray-200 rounded-lg py-2 px-2 text-xs focus:ring-2 focus:ring-emerald-500/20 focus:border-emerald-500 outline-none transition-all cursor-pointer shadow-sm" value={draftCustomerFilters.department} onChange={(e) => setDraftCustomerFilters(prev => ({ ...prev, department: e.target.value }))}>
+                            <select className="w-full bg-white border border-gray-200 rounded-lg py-2 px-2 text-xs focus:ring-2 focus:ring-emerald-500/20 focus:border-emerald-500 outline-none transition-all cursor-pointer shadow-sm" value={draftCustomerFilters.department} onChange={(e) => setDraftCustomerFilters(prev => ({ ...prev, department: e.target.value, manager: '' }))}>
                               <option value="">所有部门</option>
                               {uniqueDepts.map(d => <option key={d} value={d}>{d}</option>)}
                             </select>