One emoji, one reaction: variation selectors made canonical

A heart reaction arrived as ❤ from some servers and as ❤️ (with the
emoji variation selector) from others, and a persona's own reaction kept
whatever it was given: the same emoji was two reactions, counted apart.
The selector is now dropped and put back only on a symbol that shows as
text without it (U+2000 to U+2BFF), so every heart is ❤️ and every 🔥
is 🔥. Found by the town's Hollo pair.

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

PrivaPub.Tests/Federation/ReactionTests.cs

@@ -17,6 +17,9 @@ namespace PrivaPub.Tests.Federation
 		[InlineData(":blobcat@k.example:", "blobcat")]
 		[InlineData("👍🏽", "👍🏽")]
 		[InlineData("❤️", "❤️")]
+		[InlineData("❤", "❤️")]
+		[InlineData("✌", "✌️")]
+		[InlineData("🔥\uFE0F", "🔥")]
 		[InlineData("nope", null)]
 		[InlineData("👍👍", null)]
 		[InlineData(":unknown:", null)]

PrivaPub/Domain/Social/Reactions.cs

@@ -178,6 +178,11 @@ namespace PrivaPub.Domain.Social
 					return requireKnownCustom ? default : new Picked(bare, default);
 				return new Picked(bare, emoji.URL);
 			}
+			// one emoji, one name: ❤ and ❤️ (with the emoji variation selector) were two reactions, counted apart. The selector
+			// is dropped, then put back on a symbol that shows as text without it (U+2000 to U+2BFF: ❤, ☺, ✌...)
+			text = text.Replace("\uFE0F", "");
+			if (text.Length == 1 && text[0] is >= '\u2000' and <= '\u2BFF')
+				text += "\uFE0F";
 			if (text.Any(c => c < 128 || char.IsWhiteSpace(c)) || new StringInfo(text).LengthInTextElements != 1)
 				return default;
 			return new Picked(text, default);