feat: custom emoji in chat

lib/widgets/custom_emoji.dart

@@ -0,0 +1,39 @@
+import 'package:cached_network_image/cached_network_image.dart';
+import 'package:collection/collection.dart';
+import 'package:flutter/widgets.dart';
+import 'package:zap_stream_flutter/imgproxy.dart';
+
+class CustomEmoji extends StatelessWidget {
+  final List<List<String>> tags;
+  final String emoji;
+  final double? size;
+
+  const CustomEmoji({
+    super.key,
+    required this.tags,
+    required this.emoji,
+    this.size,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final cleanedEmojiName =
+        emoji.startsWith(":") && emoji.endsWith(":")
+            ? emoji.substring(1, emoji.length - 1)
+            : emoji;
+
+    final customEmoji =
+        tags.firstWhereOrNull(
+          (t) => t[0] == "emoji" && t[1] == cleanedEmojiName,
+        )?[2];
+    if (customEmoji != null) {
+      return CachedNetworkImage(
+        imageUrl: proxyImg(context, customEmoji),
+        height: size ?? 16,
+        width: size ?? 16,
+      );
+    } else {
+      return Text(emoji);
+    }
+  }
+}