feat: Display list of remote users who liked a post

This change implements the ability to display a list of remote users
who have liked a post on an individual entry page (collection post).

Key changes include:

• Added a RemoteLikers []*RemoteUser field to the PublicPost struct in posts.go.
• Implemented a new database function getRemoteLikersForPost(postID string) in database.go to fetch likers by joining remote_likes and remoteusers tables.
• Modified the GetPost function in database.go to call getRemoteLikersForPost and populate the RemoteLikers field.
• Updated the templates/collection-post.tmpl template to iterate over RemoteLikers and display each user's handle as a link to their profile.