chore(ci, dto): update build workflow and enhance post DTOs

- Added NODE_NO_WARNINGS environment variable to build and deploy workflows.
- Upgraded actions/upload-artifact and actions/download-artifact to version 4 in the build workflow.
- Introduced ContentEditedAt field in PostResponse and PostDetailResponse DTOs to track content modification timestamps.
- Updated post conversion functions to include ContentEditedAt in responses.
- Ensured ContentEditedAt is set during post updates in the repository.

internal/handler/post_handler.go

@@ -112,9 +112,10 @@ func (h *PostHandler) GetByID(c *gin.Context) {
 		IsPinned:       post.IsPinned,
 		IsLocked:       post.IsLocked,
 		IsVote:         post.IsVote,
-		CreatedAt:      dto.FormatTime(post.CreatedAt),
-		UpdatedAt:      dto.FormatTime(post.UpdatedAt),
-		Author:         authorWithFollowStatus,
+		CreatedAt:       dto.FormatTime(post.CreatedAt),
+		UpdatedAt:       dto.FormatTime(post.UpdatedAt),
+		ContentEditedAt: dto.FormatTimePointer(post.ContentEditedAt),
+		Author:          authorWithFollowStatus,
 		IsLiked:        isLiked,
 		IsFavorited:    isFavorited,
 	}