优化合同气瓶绑定与启用失败提示

- 将绑定气瓶入口移至合同列表，仅草稿合同显示
- 自动预填所选合同并保留返回路径
- 细分附件、有效期、气瓶绑定和状态校验失败原因
- 增加前后端回归检查及中文操作日志

backend/api/internal/logic/platform/gasorder/contract_change_error_test.go

@@ -0,0 +1,43 @@
+// 功能：验证合同生命周期业务错误可安全、明确地返回前端。
+// 版本：v1.0.0
+package gasorder
+
+import (
+	"errors"
+	"testing"
+)
+
+// TestContractChangeBusinessErrors 验证所有允许透传的合同业务原因。
+func TestContractChangeBusinessErrors(t *testing.T) {
+	businessErrors := []error{
+		errContractCannotActivate,
+		errContractCannotTerminate,
+		errContractAttachment,
+		errContractNotEffective,
+		errContractExpired,
+		errContractNoProduct,
+	}
+	for _, businessErr := range businessErrors {
+		if !isContractChangeBusinessError(businessErr) {
+			t.Fatalf("业务错误未被识别：%s", businessErr)
+		}
+	}
+	if isContractChangeBusinessError(errors.New("database connection failed")) {
+		t.Fatal("内部错误不应透传给前端")
+	}
+}
+
+// TestContractActivationErrorMessages 验证关键启用失败原因保持清晰中文。
+func TestContractActivationErrorMessages(t *testing.T) {
+	want := map[error]string{
+		errContractAttachment:   "合同附件无效，请重新上传有效的 PDF 文件后再启用",
+		errContractNotEffective: "合同尚未到生效时间，暂时不能启用",
+		errContractExpired:      "合同已到期，请调整到期时间或续签后再启用",
+		errContractNoProduct:    "合同尚未绑定有效气瓶，请先绑定气瓶后再启用",
+	}
+	for businessErr, message := range want {
+		if businessErr.Error() != message {
+			t.Fatalf("错误提示不清晰：得到 %q，期望 %q", businessErr.Error(), message)
+		}
+	}
+}

backend/api/internal/logic/platform/gasorder/gasorder.go

@@ -21,6 +21,16 @@ var gasorderCreatorModels = map[string]any{
 	"delivery": &models.DeliveryBasic{}, "gas": &models.GasBasic{},
 }
 
+// 合同生命周期业务错误会直接返回前端，避免把可处理原因模糊成参数错误。
+var (
+	errContractCannotActivate  = errors.New("当前合同状态不允许启用，请刷新页面后重试")
+	errContractCannotTerminate = errors.New("仅生效中的合同可以终止")
+	errContractAttachment      = errors.New("合同附件无效，请重新上传有效的 PDF 文件后再启用")
+	errContractNotEffective    = errors.New("合同尚未到生效时间，暂时不能启用")
+	errContractExpired         = errors.New("合同已到期，请调整到期时间或续签后再启用")
+	errContractNoProduct       = errors.New("合同尚未绑定有效气瓶，请先绑定气瓶后再启用")
+)
+
 func ListGasorderContract(ctx *gin.Context) { common.ListResource(ctx, &models.GasorderContract{}) }
 func GetGasorderContract(ctx *gin.Context)  { getGasorderContract(ctx) }
 func ListGasorderContractProduct(ctx *gin.Context) {
@@ -337,24 +347,30 @@ func changeGasorderContract(ctx *gin.Context, action string, target int) {
 			return err
 		}
 		if action == "activate" && contract.ContractStatus != common.StatusDraft && contract.ContractStatus != common.StatusTerminated {
-			return errors.New("contract cannot be activated")
+			return errContractCannotActivate
 		}
 		if action == "terminate" && contract.ContractStatus != common.StatusActive {
-			return errors.New("contract cannot be terminated")
+			return errContractCannotTerminate
 		}
 		if target == common.StatusActive {
 			attachmentPath, attachmentErr := contractAttachmentPath(contract.FileURI, false)
 			if attachmentErr != nil || !validStoredContractPDF(attachmentPath) {
-				return errors.New("contract has no valid attachment")
+				return errContractAttachment
 			}
 			now := time.Now()
-			if contract.EffectiveAt.After(now) || (contract.ExpiredAt != nil && !contract.ExpiredAt.After(now)) {
-				return errors.New("contract outside effective period")
+			if contract.EffectiveAt.After(now) {
+				return errContractNotEffective
+			}
+			if contract.ExpiredAt != nil && !contract.ExpiredAt.After(now) {
+				return errContractExpired
 			}
 			var productCount int64
 			if err := tx.Model(&models.GasorderContractProduct{}).
 				Where("gasorder_contract_id = ? AND unbound_at IS NULL", contract.ID).Count(&productCount).Error; err != nil || productCount == 0 {
-				return errors.New("contract has no active product")
+				if err != nil {
+					return err
+				}
+				return errContractNoProduct
 			}
 		}
 		if err := tx.Model(&contract).Update("contract_status", target).Error; err != nil {
@@ -364,12 +380,26 @@ func changeGasorderContract(ctx *gin.Context, action string, target int) {
 		return tx.Create(contractRevision(contract, action, request.Reason, operatorIdentity, operatorName)).Error
 	})
 	if err != nil {
-		infra.Response.Error(ctx, errcode.ErrInvalidArgument)
+		if isContractChangeBusinessError(err) {
+			infra.Response.Error(ctx, err)
+		} else {
+			infra.Response.Error(ctx, errcode.ErrInvalidArgument)
+		}
 		return
 	}
 	infra.Response.Success(ctx, gin.H{"updated": true, "contract_status": target})
 }
 
+// isContractChangeBusinessError 仅允许预定义业务原因透传，避免泄露数据库内部错误。
+func isContractChangeBusinessError(err error) bool {
+	return errors.Is(err, errContractCannotActivate) ||
+		errors.Is(err, errContractCannotTerminate) ||
+		errors.Is(err, errContractAttachment) ||
+		errors.Is(err, errContractNotEffective) ||
+		errors.Is(err, errContractExpired) ||
+		errors.Is(err, errContractNoProduct)
+}
+
 func contractRevision(contract models.GasorderContract, action, reason, operatorIdentity, operatorName string) *models.GasorderContractRevision {
 	return &models.GasorderContractRevision{
 		Entity:             models.Entity{Identity: models.NewIdentity(), Status: common.StatusEnable},