feat: default steps are read only

server/internal/api/workflows.go

@@ -1,6 +1,7 @@
 package api
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -185,6 +186,10 @@ func updateStep(c *gin.Context) {
 		return
 	}
 	if err := services.UpdateStep(auth.InstanceID(c), c.Param("id"), s); err != nil {
+		if errors.Is(err, services.ErrDefaultStep) {
+			c.JSON(http.StatusConflict, gin.H{"error": err.Error()})
+			return
+		}
 		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
 		return
 	}
@@ -194,6 +199,10 @@ func updateStep(c *gin.Context) {
 
 func deleteStep(c *gin.Context) {
 	if err := services.DeleteStep(auth.InstanceID(c), c.Param("id")); err != nil {
+		if errors.Is(err, services.ErrDefaultStep) {
+			c.JSON(http.StatusConflict, gin.H{"error": err.Error()})
+			return
+		}
 		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
 		return
 	}