A group's owner sees its members and requests, declines and removes

/clientapi/group had no way to see who is in a group or asks to join it,
so a circle's owner could not answer a request from elsewhere. Now:
- GET /clientapi/group/members: the members (local and remote, with their
  role) and the pending requests, for the group's owner and moderators
  only;
- POST /clientapi/group/reject: declines a request, telling the asker's
  server with a Reject of its Follow;
- POST /clientapi/group/remove: takes a member out (never the owner): a
  persona here stops following the group, one elsewhere gets a Reject of
  its Follow, as Mastodon removes a follower.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

PrivaPub.ClientModels/Group/ViewGroupMember.cs

@@ -0,0 +1,15 @@
+namespace PrivaPub.ClientModels.Group
+{
+	// someone in a group, or asking to join it, as its owner and moderators see them
+	public class ViewGroupMember
+	{
+		public string ActorUri { get; set; }
+		public string Handle { get; set; }
+		public string Name { get; set; }
+		public string PictureUrl { get; set; }
+		public bool IsLocal { get; set; }
+		public bool IsPending { get; set; }
+		public string Role { get; set; }//owner, moderator, member
+		public DateTime Since { get; set; }
+	}
+}