feat: 支持账单编辑（PATCH /api/bills/:id）

server/repository/mongo/repository.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/bson/primitive"
 	"go.mongodb.org/mongo-driver/mongo"
 	"go.mongodb.org/mongo-driver/mongo/options"
 
@@ -383,6 +384,40 @@ func (r *Repository) GetMonthlyStats() ([]model.MonthlyStat, error) {
 	return stats, nil
 }
 
+// UpdateCleanedBillByID 按 ID 更新清洗后的账单，并返回更新后的记录
+func (r *Repository) UpdateCleanedBillByID(id string, updates map[string]interface{}) (*model.CleanedBill, error) {
+	if r.cleanedCollection == nil {
+		return nil, fmt.Errorf("cleaned collection not initialized")
+	}
+
+	oid, err := primitive.ObjectIDFromHex(id)
+	if err != nil {
+		return nil, fmt.Errorf("invalid id: %w", err)
+	}
+
+	if len(updates) == 0 {
+		return nil, fmt.Errorf("no updates")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	filter := bson.M{"_id": oid}
+	update := bson.M{"$set": updates}
+	opts := options.FindOneAndUpdate().SetReturnDocument(options.After)
+
+	var updated model.CleanedBill
+	err = r.cleanedCollection.FindOneAndUpdate(ctx, filter, update, opts).Decode(&updated)
+	if err != nil {
+		if err == mongo.ErrNoDocuments {
+			return nil, repository.ErrNotFound
+		}
+		return nil, fmt.Errorf("update bill failed: %w", err)
+	}
+
+	return &updated, nil
+}
+
 // GetClient 获取 MongoDB 客户端（用于兼容旧代码）
 func (r *Repository) GetClient() *mongo.Client {
 	return r.client