chore(server): send comment notification to all repliers (#13063)

close AF-2714



#### PR Dependency Tree


* **PR #13063** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
  * Added the ability to list all replies for a specific comment.

* **Bug Fixes**
* Improved notification delivery for comment replies, ensuring all
relevant users (comment author, document owner, and all repliers) are
notified appropriately.

* **Tests**
* Added and updated tests to verify correct notification behavior and
the new reply listing functionality.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/models/comment.ts

@@ -300,6 +300,13 @@ export class CommentModel extends BaseModel {
     })) as Reply | null;
   }
 
+  async listReplies(workspaceId: string, docId: string, commentId: string) {
+    return (await this.db.reply.findMany({
+      where: { workspaceId, docId, commentId, deletedAt: null },
+      orderBy: { sid: 'asc' },
+    })) as Reply[];
+  }
+
   /**
    * Update a reply content
    * @param input - The reply update input