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/database/schemas/comments.ts

@@ -12,6 +12,9 @@ export const comments = pgTable(
 		userId: uuid("user_id")
 			.notNull()
 			.references(() => users.uuid, { onDelete: "cascade" }),
+		parentId: uuid("parent_id").references(() => comments.id, {
+			onDelete: "cascade",
+		}),
 		text: text("text").notNull(),
 		createdAt: timestamp("created_at", { withTimezone: true })
 			.notNull()
@@ -24,6 +27,7 @@ export const comments = pgTable(
 	(table) => ({
 		contentIdIdx: index("comments_content_id_idx").on(table.contentId),
 		userIdIdx: index("comments_user_id_idx").on(table.userId),
+		parentIdIdx: index("comments_parent_id_idx").on(table.parentId),
 	}),
 );