feat: import Chinese-localized Buzz source snapshot

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

mobile/lib/features/channels/mentions/mention_candidates_provider.dart

@@ -0,0 +1,107 @@
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+import '../../../shared/crypto/nip_oa.dart';
+import '../../../shared/mentions/agent_identity_provider.dart';
+import '../../../shared/relay/relay.dart';
+import '../../profile/user_cache_provider.dart';
+import '../../profile/user_profile.dart';
+import '../channel.dart';
+import '../channel_management_provider.dart';
+import '../channels_provider.dart';
+import 'mention_candidates.dart';
+import 'mention_ranking.dart';
+
+/// Debounce before a mention query hits the relay search endpoint.
+const _mentionSearchDebounce = Duration(milliseconds: 250);
+
+/// Global user search for mention autocomplete — kind:0 prefix search via
+/// the relay HTTP bridge. Mirrors desktop's `useInfiniteUserSearchQuery`
+/// feeding `useMentions` (source 4: people and agents outside the channel).
+///
+/// Debounced: the provider waits [_mentionSearchDebounce] before querying;
+/// keystrokes dispose the stale family member so its request never fires.
+final mentionUserSearchProvider = FutureProvider.autoDispose
+    .family<List<UserProfile>, String>((ref, query) async {
+      final trimmed = query.trim();
+      if (trimmed.isEmpty) return const [];
+
+      var disposed = false;
+      ref.onDispose(() => disposed = true);
+      await Future<void>.delayed(_mentionSearchDebounce);
+      if (disposed) return const [];
+
+      final session = ref.read(relaySessionProvider.notifier);
+      final events = await session.queryRelay([
+        NostrFilters.searchUsers(trimmed),
+      ]);
+
+      // Keep only the latest kind:0 event per pubkey (the bridge does not
+      // honor the `kinds` filter under search, and may return several
+      // profile revisions — mirrors desktop's `list_user_search_results`).
+      final latestByPubkey = <String, NostrEvent>{};
+      for (final event in events) {
+        if (event.kind != 0) continue;
+        final pk = event.pubkey.toLowerCase();
+        final current = latestByPubkey[pk];
+        if (current == null || event.createdAt > current.createdAt) {
+          latestByPubkey[pk] = event;
+        }
+      }
+
+      return [
+        for (final event in latestByPubkey.values) _profileFromEvent(event),
+      ];
+    });
+
+UserProfile _profileFromEvent(NostrEvent event) {
+  final data = ProfileData.fromEvent(event);
+  return UserProfile(
+    pubkey: event.pubkey.toLowerCase(),
+    displayName: data.displayName,
+    avatarUrl: data.avatarUrl,
+    about: data.about,
+    nip05Handle: data.nip05,
+    ownerPubkey: verifiedOaOwnerPubkey(event.tags, event.pubkey),
+  );
+}
+
+/// Ranked mention candidates for a channel + query. Channel members first,
+/// then non-member relay agents the user can actually reach, then global
+/// search results; ordering matches desktop's `rankMentionCandidates`.
+final mentionCandidatesProvider = Provider.family
+    .autoDispose<List<MentionCandidate>, ({String channelId, String query})>((
+      ref,
+      args,
+    ) {
+      final members =
+          ref.watch(channelMembersProvider(args.channelId)).asData?.value ??
+          const <ChannelMember>[];
+      final relayAgents =
+          ref.watch(agentDirectoryProvider).asData?.value ??
+          const <AgentDirectoryEntry>[];
+      final owners = ref.watch(agentOwnersProvider).asData?.value ?? const {};
+      final channels =
+          ref.watch(channelsProvider).asData?.value ?? const <Channel>[];
+      final userCache = ref.watch(userCacheProvider);
+      final currentPubkey = ref.watch(currentPubkeyProvider);
+      final searchResults =
+          ref.watch(mentionUserSearchProvider(args.query)).asData?.value ??
+          const <UserProfile>[];
+
+      final sharedChannelIds = {
+        for (final channel in channels)
+          if (channel.isMember && !channel.isArchived) channel.id,
+      };
+
+      final candidates = buildMentionCandidates(
+        members: members,
+        relayAgents: relayAgents,
+        sharedChannelIds: sharedChannelIds,
+        userCache: userCache,
+        ownerByAgentPubkey: owners,
+        searchResults: searchResults,
+        currentPubkey: currentPubkey,
+      );
+
+      return rankMentionCandidates(candidates, args.query);
+    });