feat: import Chinese-localized Buzz source snapshot

Signed-off-by: cls_宁波本机 <908705107@qq.com>

mobile/lib/shared/emoji/emoji_data.dart

@@ -0,0 +1,154 @@
+import 'package:flutter/foundation.dart';
+
+/// The standard (Unicode) emoji set, projected from the same emoji-mart dataset
+/// desktop uses.
+///
+/// The asset at `assets/emoji/emoji-data.json` is generated by
+/// `just mobile-emoji-data`; ids here are emoji-mart ids, which are exactly the
+/// `:shortcode:` values desktop emits from its picker and resolves in
+/// `emojiDisplayName`. Keeping both clients on one dataset is what stops a
+/// shortcode from meaning different things on mobile and desktop.
+@immutable
+class EmojiEntry {
+  /// emoji-mart id, i.e. the shortcode without the surrounding colons.
+  final String id;
+
+  /// Human-readable name, e.g. `Index Pointing Up`.
+  final String name;
+
+  /// Search keywords from the dataset.
+  final List<String> keywords;
+
+  /// The default-skin glyph.
+  final String native;
+
+  /// Position within emoji-mart's skin list. The default skin is zero.
+  final int skinIndex;
+
+  /// Owning category id, e.g. `people`.
+  final String categoryId;
+
+  const EmojiEntry({
+    required this.id,
+    required this.name,
+    required this.keywords,
+    required this.native,
+    required this.categoryId,
+    this.skinIndex = 0,
+  });
+
+  /// Unique tile id while preserving the desktop-identical shortcode for the
+  /// default skin.
+  String get tileId => skinIndex == 0 ? id : '$id-$skinIndex';
+}
+
+/// One dataset category, in emoji-mart's own order.
+@immutable
+class EmojiCategory {
+  final String id;
+  final List<EmojiEntry> emoji;
+
+  const EmojiCategory({required this.id, required this.emoji});
+
+  /// Title-cased label for the category rail.
+  String get label => switch (id) {
+    'people' => 'Smileys & People',
+    'nature' => 'Animals & Nature',
+    'foods' => 'Food & Drink',
+    'activity' => 'Activity',
+    'places' => 'Travel & Places',
+    'objects' => 'Objects',
+    'symbols' => 'Symbols',
+    'flags' => 'Flags',
+    _ => id,
+  };
+}
+
+/// Parsed emoji dataset: ordered categories, a flat list for search, and a
+/// reverse glyph index for resolving a reaction back to its shortcode.
+@immutable
+class EmojiDataset {
+  final List<EmojiCategory> categories;
+
+  /// Every entry, in category order. Search scans this.
+  final List<EmojiEntry> all;
+
+  /// Glyph to `:shortcode:`. Mirrors desktop's `emojiDisplayName`.
+  final Map<String, String> nativeToShortcode;
+
+  const EmojiDataset({
+    required this.categories,
+    required this.all,
+    required this.nativeToShortcode,
+  });
+
+  static const empty = EmojiDataset(
+    categories: [],
+    all: [],
+    nativeToShortcode: {},
+  );
+
+  bool get isEmpty => all.isEmpty;
+
+  /// Resolve a reaction value to something displayable as a name: a custom
+  /// emoji's `:shortcode:` passes through, a Unicode glyph maps to its
+  /// shortcode, and anything unknown falls back to itself.
+  String displayName(String emoji) {
+    final trimmed = emoji.trim();
+    if (trimmed.startsWith(':') && trimmed.endsWith(':')) return trimmed;
+    return nativeToShortcode[trimmed] ?? trimmed;
+  }
+
+  /// Parse the generated asset. Runs on a background isolate via `compute`, so
+  /// it must stay a top-level-callable pure function over plain JSON.
+  static EmojiDataset fromJson(Map<String, dynamic> json) {
+    final rawEmoji = (json['emoji'] as Map).cast<String, dynamic>();
+    final rawCategories = (json['categories'] as List).cast<dynamic>();
+
+    final categories = <EmojiCategory>[];
+    final all = <EmojiEntry>[];
+    final nativeToShortcode = <String, String>{};
+
+    for (final rawCategory in rawCategories) {
+      final category = (rawCategory as Map).cast<String, dynamic>();
+      final categoryId = category['id'] as String;
+      final entries = <EmojiEntry>[];
+
+      for (final rawId in (category['emoji'] as List).cast<dynamic>()) {
+        final id = rawId as String;
+        final record = (rawEmoji[id] as Map?)?.cast<String, dynamic>();
+        if (record == null) continue;
+        // Older committed assets used one string; accept that shape so the
+        // parser remains safe while generated assets move to all skin variants.
+        final natives = switch (record['u']) {
+          final List values => values.cast<String>(),
+          final String value => [value],
+          _ => const <String>[],
+        };
+        for (final (skinIndex, native) in natives.indexed) {
+          final entry = EmojiEntry(
+            id: id,
+            name: record['n'] as String,
+            keywords: (record['k'] as List).cast<String>(),
+            native: native,
+            categoryId: categoryId,
+            skinIndex: skinIndex,
+          );
+          entries.add(entry);
+          all.add(entry);
+          // First writer wins so the earliest category owns a shared glyph,
+          // matching desktop's map build order.
+          nativeToShortcode.putIfAbsent(entry.native, () => ':$id:');
+        }
+      }
+
+      categories.add(EmojiCategory(id: categoryId, emoji: entries));
+    }
+
+    return EmojiDataset(
+      categories: categories,
+      all: all,
+      nativeToShortcode: nativeToShortcode,
+    );
+  }
+}