feat: add comment replies and liking functionality

- Introduced support for nested comment replies in both frontend and backend.
- Added comment liking and unliking features, including like count and "isLiked" state tracking.
- Updated database schema with `parentId` and new `comment_likes` table.
- Enhanced UI for threaded comments and implemented display of like counts and reply actions.
- Refactored APIs and repositories to support replies, likes, and enriched comment data.

backend/src/comments/dto/create-comment.dto.ts

@@ -1,8 +1,18 @@
-import { IsNotEmpty, IsString, MaxLength } from "class-validator";
+import {
+	IsNotEmpty,
+	IsOptional,
+	IsString,
+	IsUUID,
+	MaxLength,
+} from "class-validator";
 
 export class CreateCommentDto {
 	@IsString()
 	@IsNotEmpty()
 	@MaxLength(1000)
 	text!: string;
+
+	@IsOptional()
+	@IsUUID()
+	parentId?: string;
 }