feat(client): 财务筛选增加往来单位并统一自定义时间组件（两端，原型同步）

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

client/lib/providers/finance_provider.dart

@@ -22,6 +22,7 @@ class FinanceListNotifier extends AsyncNotifier<PageResult<FinanceRecord>> {
   String _month = '';
   String _startDate = '';
   String _endDate = '';
+  int? _partnerId;
 
   @override
   Future<PageResult<FinanceRecord>> build() {
@@ -35,6 +36,7 @@ class FinanceListNotifier extends AsyncNotifier<PageResult<FinanceRecord>> {
           month: _month.isEmpty ? null : _month,
           startDate: _startDate.isEmpty ? null : _startDate,
           endDate: _endDate.isEmpty ? null : _endDate,
+          partnerId: _partnerId,
           page: _page,
           pageSize: _pageSize,
         );
@@ -46,6 +48,13 @@ class FinanceListNotifier extends AsyncNotifier<PageResult<FinanceRecord>> {
     reload();
   }
 
+  /// 往来单位筛选（工具栏 ComboSearchField / 移动端 chip→sheet 共用）。
+  void setPartner(int? partnerId) {
+    _partnerId = partnerId;
+    _page = 1;
+    reload();
+  }
+
   void setMonth(String month) {
     _month = month;
     _startDate = '';