P6: custom emoji, fuller remote profiles, and polls both ways

- Custom emoji (Emoji tags) on posts, display names, bios and profile fields, at most 64 per object, proxied, in
  Status.emojis and Account.emojis.
- Remote profiles keep their header, profile fields, locked flag, published date, movedTo, indexable, memorial and
  image descriptions (a locked GoToSocial account no longer shows as open).
- Polls: incoming Questions (Mastodon, Misskey, Pleroma, GoToSocial shapes) with counts, voters, end and closed;
  our own polls from the Mastodon API go out as Questions; votes in are counted once per voter and never become
  replies; personas vote on other servers' polls with one Note per choice; counts refresh with an Update at most every
  three minutes; a poll closes on time and tells its voters and its author. GET /api/v1/polls/:id and POST
  /api/v1/polls/:id/votes.
- An Update without a newer `updated` only refreshes poll, video, audio and event details and leaves no revision.

Checked live against GoToSocial: each side's poll reaches the other as a poll and each side's vote is counted.

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

PrivaPub/Federation/Objects/ObjectShapes.cs

@@ -16,6 +16,8 @@ namespace PrivaPub.Federation.Objects
 		const int MaxCaptions = 20;
 		const int MaxPlaces = 4;
 		const int CoverMaxWidth = 1280;
+		const int MaxEmojis = 64;
+		const int MaxPollOptions = 20;
 
 		static readonly Dictionary<string, string> MediaTypesByExtension = new(StringComparer.OrdinalIgnoreCase)
 		{
@@ -81,6 +83,52 @@ namespace PrivaPub.Federation.Objects
 				?? usable.Select(c => c.Url).FirstOrDefault();
 		}
 
+		public static List<CustomEmoji> Emojis(JsonNode tags) =>
+			Objects(tags)
+				.Where(t => Value(t, "type") == "Emoji")
+				.Select(t => new CustomEmoji
+				{
+					Shortcode = Value(t, "name")?.Trim(':'),
+					URL = MediaLink(t["icon"]).Url,
+					Updated = Moment(Value(t, "updated"))
+				})
+				.Where(e => !string.IsNullOrEmpty(e.Shortcode) && e.Shortcode.Length <= 100 && Shortcode().IsMatch(e.Shortcode) && Origin.Of(e.URL) != default)
+				.DistinctBy(e => e.Shortcode)
+				.Take(MaxEmojis)
+				.ToList();
+
+		public static PostPoll Poll(JsonObject note)
+		{
+			if (Value(note, "type") != "Question")
+				return default;
+			var multiple = note["anyOf"] is JsonArray;
+			var options = Objects(note[multiple ? "anyOf" : "oneOf"])
+				.Select(o => new PollOption
+				{
+					Title = Text(Value(o, "name"), 200),
+					Votes = o["replies"] is JsonObject replies && Int(replies, "totalItems") is { } total ? total : Int(o, "_misskey_votes") ?? 0
+				})
+				.Where(o => o.Title != default)
+				.Take(MaxPollOptions)
+				.ToList();
+			if (options.Count < 2)
+				return default;
+			var closedAt = note["closed"] switch
+			{
+				JsonValue value when value.TryGetValue<bool>(out var closed) => closed ? Moment(Value(note, "endTime")) ?? DateTime.UtcNow : default(DateTime?),
+				JsonValue value when value.TryGetValue<string>(out var at) => Moment(at),
+				_ => default
+			};
+			return new PostPoll
+			{
+				Options = options,
+				Multiple = multiple,
+				ExpiresAt = Moment(Value(note, "endTime")),
+				ClosedAt = closedAt,
+				VotersCount = Int(note, "votersCount")
+			};
+		}
+
 		public static string Cover(JsonObject note) =>
 			Image(note["image"]) ?? Image(note["icon"]) ?? (note["preview"] is JsonObject preview && Value(preview, "type") == "Image" ? Image(preview) : default);
 
@@ -284,6 +332,9 @@ namespace PrivaPub.Federation.Objects
 		static bool? Bool(JsonObject node, string property) =>
 			node?[property] is JsonValue value && value.TryGetValue<bool>(out var flag) ? flag : (bool?)null;
 
+		[GeneratedRegex(@"^[\w+\-.@]+$")]
+		private static partial Regex Shortcode();
+
 		[GeneratedRegex("<[^>]*>")]
 		private static partial Regex Tags();