Replies a post's author approves (FEP-5624), checked live with PeerTube

PeerTube puts canReply on a video whose comments wait for approval, and answers each comment with ApproveReply. A
persona's reply to such a post now waits (privapub.approval: pending), its Create going to the author alone; the
author's ApproveReply, signed by the author and naming the post answered, lets it out to its audience with
replyApproval, and RejectReply leaves it ours. A null canReply (PeerTube's open comments) says nothing; an empty one
refuses. The PeerTube scenario holds a comment for review and approves it through PeerTube's API (28 checks).

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

PrivaPub/Federation/Objects/ObjectShapes.cs

@@ -102,16 +102,23 @@ namespace PrivaPub.Federation.Objects
 
 		// one rule of a post's interactionPolicy (GoToSocial, FEP-044f): who may, automatically or once asked; the old names
 		// (always, approvalRequired) too. A rule left out means anyone, automatically
+		static List<string> Who(JsonNode node) => node switch
+		{
+			JsonArray array => array.Select(Id).Where(id => id != default).Take(MaxAudience).ToList(),
+			JsonNode single when Id(single) is { } id => new List<string> { id },
+			_ => new List<string>()
+		};
+
+		// FEP-5624's canReply (PeerTube's, on a video whose comments wait for approval): who may reply, each reply then
+		// approved by the author with an ApproveReply, or refused with a RejectReply; null when the post states none (PeerTube
+		// sends null for a video whose comments are open, and an empty list where they are closed)
+		public static InteractionRule ReplyApprovals(JsonObject note) =>
+			note["canReply"] is { } canReply ? new InteractionRule { Manual = Who(canReply) } : default;
+
 		public static InteractionRule Policy(JsonObject note, string rule)
 		{
 			if (note["interactionPolicy"] is not JsonObject policy || policy[rule] is not JsonObject allowed)
 				return default;
-			static List<string> Who(JsonNode node) => node switch
-			{
-				JsonArray array => array.Select(Id).Where(id => id != default).Take(MaxAudience).ToList(),
-				JsonNode single when Id(single) is { } id => new List<string> { id },
-				_ => new List<string>()
-			};
 			return new InteractionRule
 			{
 				Automatic = Who(allowed["automaticApproval"] ?? allowed["always"]),