feat: import Chinese-localized Buzz source snapshot

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

mobile/lib/features/activity/feed_item.dart

@@ -0,0 +1,137 @@
+import 'package:flutter/foundation.dart';
+
+@immutable
+class FeedItem {
+  final String id;
+  final int kind;
+  final String pubkey;
+  final String content;
+  final int createdAt;
+  final String? channelId;
+  final String channelName;
+  final List<List<String>> tags;
+  final String
+  category; // "mention", "needs_action", "activity", "agent_activity"
+
+  const FeedItem({
+    required this.id,
+    required this.kind,
+    required this.pubkey,
+    required this.content,
+    required this.createdAt,
+    required this.channelId,
+    required this.channelName,
+    required this.tags,
+    required this.category,
+  });
+
+  factory FeedItem.fromJson(Map<String, dynamic> json) => FeedItem(
+    id: json['id'] as String,
+    kind: json['kind'] as int,
+    pubkey: json['pubkey'] as String,
+    content: json['content'] as String,
+    createdAt: json['created_at'] as int,
+    channelId: json['channel_id'] as String?,
+    channelName: (json['channel_name'] as String?) ?? '',
+    tags:
+        (json['tags'] as List<dynamic>?)
+            ?.map((t) => (t as List<dynamic>).map((e) => e as String).toList())
+            .toList() ??
+        const [],
+    category: json['category'] as String,
+  );
+
+  /// The message whose thread directly contains this item, when this event is
+  /// a reply. For nested replies this is the direct parent, not the outer root.
+  String? get threadHeadId {
+    for (final tag in tags) {
+      if (tag.length >= 4 && tag[0] == 'e' && tag[3] == 'reply') {
+        return tag[1];
+      }
+    }
+    return null;
+  }
+
+  /// Human-readable headline based on event kind and category.
+  String get headline {
+    switch (kind) {
+      case 45001:
+        return 'Forum post';
+      case 45003:
+        return 'Forum reply';
+      case 46010:
+        return 'Approval requested';
+      case 43001:
+        return 'Job requested';
+      case 43002:
+        return 'Job accepted';
+      case 43003:
+        return 'Progress update';
+      case 43004:
+        return 'Job result';
+      case 43005:
+        return 'Job cancelled';
+      case 43006:
+        return 'Job failed';
+      default:
+        if (category == 'mention') return 'Mention';
+        if (category == 'agent_activity') return 'Agent update';
+        return 'Channel update';
+    }
+  }
+
+  /// Trimmed content, with a fallback for empty events.
+  String get displayContent {
+    final trimmed = content.trim();
+    if (trimmed.isNotEmpty) return trimmed;
+    if (kind == 46010) return 'A workflow is waiting for approval.';
+    return 'No additional details.';
+  }
+}
+
+/// Parsed response from GET /api/feed.
+@immutable
+class HomeFeedResponse {
+  final List<FeedItem> mentions;
+  final List<FeedItem> needsAction;
+  final List<FeedItem> activity;
+  final List<FeedItem> agentActivity;
+
+  HomeFeedResponse({
+    required this.mentions,
+    required this.needsAction,
+    required this.activity,
+    required this.agentActivity,
+  });
+
+  factory HomeFeedResponse.fromJson(Map<String, dynamic> json) {
+    final feed = json['feed'] as Map<String, dynamic>;
+    return HomeFeedResponse(
+      mentions: _parseItems(feed['mentions']),
+      needsAction: _parseItems(feed['needs_action']),
+      activity: _parseItems(feed['activity']),
+      agentActivity: _parseItems(feed['agent_activity']),
+    );
+  }
+
+  /// All items merged into a single list, sorted newest-first.
+  late final List<FeedItem> all = () {
+    final items = [...mentions, ...needsAction, ...activity, ...agentActivity];
+    items.sort((a, b) => b.createdAt.compareTo(a.createdAt));
+    return List<FeedItem>.unmodifiable(items);
+  }();
+
+  bool get isEmpty =>
+      mentions.isEmpty &&
+      needsAction.isEmpty &&
+      activity.isEmpty &&
+      agentActivity.isEmpty;
+}
+
+List<FeedItem> _parseItems(dynamic json) {
+  if (json == null) return const [];
+  return (json as List<dynamic>)
+      .cast<Map<String, dynamic>>()
+      .map(FeedItem.fromJson)
+      .toList();
+}