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/index.ts

@@ -1,6 +1,7 @@
 export * from "./api_keys";
 export * from "./audit_logs";
 export * from "./categories";
+export * from "./comment_likes";
 export * from "./comments";
 export * from "./content";
 export * from "./favorites";