P6: emoji reactions in and out

- Incoming reactions in all three shapes: Misskey and Sharkey Likes carrying an emoji (`content` or
  `_misskey_reaction`), Pleroma, Akkoma and Iceshrimp.NET EmojiReacts, and their Undo. Unicode reactions are one
  grapheme; custom ones need their Emoji tag and keep its image; `:name@host:` is read as `name`. A Like whose
  content is a heart stays a favourite.
- Reactions are kept per account and emoji on our posts and on remote ones we hold, and the author of a local post
  gets a `pleroma:emoji_reaction` notification with the emoji.
- Personas react through Pleroma's API (PUT/DELETE /api/v1/pleroma/statuses/:id/reactions/:emoji, GET for the list),
  which sends an EmojiReact (or its Undo) to the post's author.
- Statuses carry `emoji_reactions` (read by Phanpy) and `pleroma.emoji_reactions`, with counts and whether the viewer
  reacted.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB

PrivaPub/Api/Mastodon/Entities/Entities.cs

@@ -161,6 +161,20 @@ namespace PrivaPub.Api.Mastodon.Entities
 		public int Down { get; set; }
 	}
 
+	public class EmojiReactionEntity
+	{
+		public string Name { get; set; }
+		public int Count { get; set; }
+		public bool Me { get; set; }
+		public string Url { get; set; }
+		public string StaticUrl { get; set; }
+	}
+
+	public class PleromaStatus
+	{
+		public List<EmojiReactionEntity> EmojiReactions { get; set; } = new();
+	}
+
 	public class PollEntity
 	{
 		public string Id { get; set; }
@@ -237,6 +251,8 @@ namespace PrivaPub.Api.Mastodon.Entities
 		public string Text { get; set; }
 		public List<object> Filtered { get; set; } = new();
 		public PrivaPubStatus Privapub { get; set; }
+		public List<EmojiReactionEntity> EmojiReactions { get; set; } = new();
+		public PleromaStatus Pleroma { get; set; }
 	}
 
 	public class MediaAttachment
@@ -305,6 +321,8 @@ namespace PrivaPub.Api.Mastodon.Entities
 		public string GroupKey { get; set; }
 		public Account Account { get; set; }
 		public Status Status { get; set; }
+		public string Emoji { get; set; }
+		public string EmojiUrl { get; set; }
 	}
 
 	public class Context