feat: improve patient flow and pricing workflow

lib/features/lab/finance/lab_finance_repository.dart

@@ -39,4 +39,30 @@ class LabFinanceRepository {
     }
     return {'pending': pending, 'paid': paid};
   }
+
+  Future<List<CounterpartyFinanceSummary>> byCounterparty(String tenantId) async {
+    final entries = await listEntries(tenantId, limit: 300);
+    final map = <String, CounterpartyFinanceSummary>{};
+
+    for (final entry in entries) {
+      final key = entry.counterpartyTenantId ?? entry.counterpartyName ?? 'unknown';
+      final current = map[key];
+      final pending = (current?.pendingAmount ?? 0) +
+          (entry.status == FinanceStatus.pending ? entry.amount : 0);
+      final paid = (current?.paidAmount ?? 0) +
+          (entry.status == FinanceStatus.paid ? entry.amount : 0);
+      map[key] = CounterpartyFinanceSummary(
+        counterpartyTenantId: entry.counterpartyTenantId,
+        counterpartyName: entry.counterpartyName ?? 'Karşı Taraf',
+        currency: entry.currency,
+        pendingAmount: pending,
+        paidAmount: paid,
+        entryCount: (current?.entryCount ?? 0) + 1,
+      );
+    }
+
+    final list = map.values.toList();
+    list.sort((a, b) => b.pendingAmount.compareTo(a.pendingAmount));
+    return list;
+  }
 }