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/comment_likes.ts

@@ -0,0 +1,21 @@
+import { pgTable, primaryKey, timestamp, uuid } from "drizzle-orm/pg-core";
+import { comments } from "./comments";
+import { users } from "./users";
+
+export const commentLikes = pgTable(
+	"comment_likes",
+	{
+		commentId: uuid("comment_id")
+			.notNull()
+			.references(() => comments.id, { onDelete: "cascade" }),
+		userId: uuid("user_id")
+			.notNull()
+			.references(() => users.uuid, { onDelete: "cascade" }),
+		createdAt: timestamp("created_at", { withTimezone: true })
+			.notNull()
+			.defaultNow(),
+	},
+	(t) => ({
+		pk: primaryKey({ columns: [t.commentId, t.userId] }),
+	}),
+);

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),
 	}),
 );
 

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";