fix(ticket): close backend core review gaps

internal/builders/ticket_builder.go

@@ -47,24 +47,16 @@ func BuildTicketWithContext(item *models.Ticket, ctx *TicketBuildContext) *respo
 	}
 	if ctx != nil && ctx.TagsByTicketID != nil {
 		ret.Tags = BuildTagResponses(ctx.TagsByTicketID[item.ID])
-	} else {
-		ret.Tags = BuildTagResponses(services.TicketService.GetTags(item.ID))
 	}
 	if item.CurrentAssigneeID > 0 {
 		if ctx != nil && ctx.Users != nil {
 			ret.CurrentAssigneeName = buildTicketUserDisplayName(ctx.Users[item.CurrentAssigneeID])
 		}
-		if ret.CurrentAssigneeName == "" {
-			ret.CurrentAssigneeName = buildTicketUserDisplayName(services.UserService.Get(item.CurrentAssigneeID))
-		}
 	}
 	if item.CustomerID > 0 {
 		if ctx != nil && ctx.Customers != nil {
 			ret.Customer = BuildCustomer(ctx.Customers[item.CustomerID])
 		}
-		if ret.Customer == nil {
-			ret.Customer = BuildCustomer(services.CustomerService.Get(item.CustomerID))
-		}
 	}
 	return ret
 }
@@ -105,9 +97,6 @@ func BuildTicketProgressWithContext(item *models.TicketProgress, ctx *TicketDeta
 		if ctx != nil && ctx.Users != nil {
 			ret.AuthorName = buildTicketUserDisplayName(ctx.Users[item.AuthorID])
 		}
-		if ret.AuthorName == "" {
-			ret.AuthorName = buildTicketUserDisplayName(services.UserService.Get(item.AuthorID))
-		}
 	}
 	return ret
 }

internal/builders/ticket_builder_test.go

@@ -58,6 +58,39 @@ func TestBuildLightweightTicket(t *testing.T) {
 	}
 }
 
+func TestBuildTicketWithoutContextLeavesOptionalLookupsEmpty(t *testing.T) {
+	now := time.Date(2026, 5, 2, 12, 30, 0, 0, time.Local)
+	ticket := &models.Ticket{
+		ID:                12,
+		TicketNo:          "TK202605020001",
+		Title:             "登录失败",
+		Description:       "客户反馈无法登录",
+		CustomerID:        3,
+		CurrentAssigneeID: 5,
+		Status:            enums.TicketStatusPending,
+		AuditFields: models.AuditFields{
+			CreateUserID:   1,
+			CreateUserName: "admin",
+			CreatedAt:      now,
+			UpdatedAt:      now,
+		},
+	}
+
+	out := BuildTicket(ticket)
+	if out == nil {
+		t.Fatalf("expected ticket response")
+	}
+	if out.Tags != nil {
+		t.Fatalf("expected tags to stay empty without context, got %+v", out.Tags)
+	}
+	if out.Customer != nil {
+		t.Fatalf("expected customer to stay empty without context, got %+v", out.Customer)
+	}
+	if out.CurrentAssigneeName != "" {
+		t.Fatalf("expected assignee name to stay empty without context, got %q", out.CurrentAssigneeName)
+	}
+}
+
 func TestBuildTicketProgress(t *testing.T) {
 	now := time.Date(2026, 5, 2, 12, 30, 0, 0, time.Local)
 	progress := &models.TicketProgress{