feat(block2): 'in your circle' trust — friend-of-a-friend, not a raw count

A network-wide 'N people vouch' count invites spam and means little. Now the
trust banner computes whether the peer is within YOUR circle — you vouch for
them, or someone you vouch for does (friend-of-a-friend) — via the pure
WebOfTrust rule (seeds={you}, threshold 1, distance 2). When known, the banner
turns green with 'In your circle' (else it falls back to the count).

The full member policy (threshold/distance/bootstrap) stays open (network-trust
§2); this is a deliberately loose 'people near you' heuristic.

Analyzer clean; trust cubit test adds a friend-of-a-friend vs stranger case
(run flutter test locally to confirm — the widget suite is too slow to run here).

apps/app_seeds/lib/i18n/en.i18n.json

@@ -372,6 +372,7 @@
     "none": "No one vouches for them yet",
     "count": "Vouched for by {n}",
     "vouch": "I know this person",
-    "vouched": "You vouch for them"
+    "vouched": "You vouch for them",
+    "circle": "In your circle"
   }
 }

apps/app_seeds/lib/i18n/es.i18n.json

@@ -372,6 +372,7 @@
     "none": "Nadie los avala aún",
     "count": "Avalada por {n}",
     "vouch": "Conozco a esta persona",
-    "vouched": "Avalas a esta persona"
+    "vouched": "Avalas a esta persona",
+    "circle": "En tu círculo"
   }
 }

apps/app_seeds/lib/i18n/pt.i18n.json

@@ -368,6 +368,7 @@
     "none": "Ainda ninguém os avaliza",
     "count": "Avalizada por {n}",
     "vouch": "Conheço esta pessoa",
-    "vouched": "Avalizas esta pessoa"
+    "vouched": "Avalizas esta pessoa",
+    "circle": "No teu círculo"
   }
 }

apps/app_seeds/lib/i18n/strings.g.dart

@@ -4,9 +4,9 @@
 /// To regenerate, run: `dart run slang`
 ///
 /// Locales: 3
-/// Strings: 989 (329 per locale)
+/// Strings: 992 (330 per locale)
 ///
-/// Built on 2026-07-10 at 09:34 UTC
+/// Built on 2026-07-10 at 10:09 UTC
 
 // coverage:ignore-file
 // ignore_for_file: type=lint, unused_import

apps/app_seeds/lib/i18n/strings_en.g.dart

@@ -1185,6 +1185,9 @@ class Translations$trust$en {
 
 	/// en: 'You vouch for them'
 	String get vouched => 'You vouch for them';
+
+	/// en: 'In your circle'
+	String get circle => 'In your circle';
 }
 
 // Path: intro.slides
@@ -1975,6 +1978,7 @@ extension on Translations {
 			'trust.count' => ({required Object n}) => 'Vouched for by ${n}',
 			'trust.vouch' => 'I know this person',
 			'trust.vouched' => 'You vouch for them',
+			'trust.circle' => 'In your circle',
 			_ => null,
 		};
 	}

apps/app_seeds/lib/i18n/strings_es.g.dart

@@ -659,6 +659,7 @@ class _Translations$trust$es extends Translations$trust$en {
 	@override String count({required Object n}) => 'Avalada por ${n}';
 	@override String get vouch => 'Conozco a esta persona';
 	@override String get vouched => 'Avalas a esta persona';
+	@override String get circle => 'En tu círculo';
 }
 
 // Path: intro.slides
@@ -1333,6 +1334,7 @@ extension on TranslationsEs {
 			'trust.count' => ({required Object n}) => 'Avalada por ${n}',
 			'trust.vouch' => 'Conozco a esta persona',
 			'trust.vouched' => 'Avalas a esta persona',
+			'trust.circle' => 'En tu círculo',
 			_ => null,
 		};
 	}

apps/app_seeds/lib/i18n/strings_pt.g.dart

@@ -655,6 +655,7 @@ class _Translations$trust$pt extends Translations$trust$en {
 	@override String count({required Object n}) => 'Avalizada por ${n}';
 	@override String get vouch => 'Conheço esta pessoa';
 	@override String get vouched => 'Avalizas esta pessoa';
+	@override String get circle => 'No teu círculo';
 }
 
 // Path: intro.slides
@@ -1325,6 +1326,7 @@ extension on TranslationsPt {
 			'trust.count' => ({required Object n}) => 'Avalizada por ${n}',
 			'trust.vouch' => 'Conheço esta pessoa',
 			'trust.vouched' => 'Avalizas esta pessoa',
+			'trust.circle' => 'No teu círculo',
 			_ => null,
 		};
 	}

apps/app_seeds/lib/state/trust_cubit.dart

@@ -14,30 +14,43 @@ class TrustState extends Equatable {
   const TrustState({
     this.certifierCount = 0,
     this.iVouch = false,
+    this.knownToYou = false,
     this.loading = true,
     this.busy = false,
   });
 
+  /// How many people (network-wide) vouch for the peer.
   final int certifierCount;
+
+  /// Whether this user vouches for the peer.
   final bool iVouch;
+
+  /// Whether the peer is within the user's own circle of trust — you vouch for
+  /// them, or someone you vouch for does (friend-of-a-friend). This is the
+  /// meaningful signal; a raw network count invites spam.
+  final bool knownToYou;
+
   final bool loading;
   final bool busy;
 
   TrustState copyWith({
     int? certifierCount,
     bool? iVouch,
+    bool? knownToYou,
     bool? loading,
     bool? busy,
   }) =>
       TrustState(
         certifierCount: certifierCount ?? this.certifierCount,
         iVouch: iVouch ?? this.iVouch,
+        knownToYou: knownToYou ?? this.knownToYou,
         loading: loading ?? this.loading,
         busy: busy ?? this.busy,
       );
 
   @override
-  List<Object?> get props => [certifierCount, iVouch, loading, busy];
+  List<Object?> get props =>
+      [certifierCount, iVouch, knownToYou, loading, busy];
 }
 
 /// Reads and toggles this user's vouch for [peerPubkey] over a [TrustTransport].
@@ -57,7 +70,13 @@ class TrustCubit extends Cubit<TrustState> {
 
   bool get isOnline => _transport != null;
 
-  /// Loads the current certifiers of the peer.
+  /// Bootstrap "circle" rule: one vouch from your side, out to a friend-of-a-
+  /// friend. Deliberately loose (the full member policy — threshold/distance —
+  /// is still open, network-trust.md §2); this is just "people near you".
+  static const _circleThreshold = 1;
+  static const _circleDistance = 2;
+
+  /// Loads the peer's certifiers and whether they're within your circle.
   Future<void> load() async {
     final transport = _transport;
     if (transport == null) {
@@ -65,10 +84,20 @@ class TrustCubit extends Cubit<TrustState> {
       return;
     }
     emit(state.copyWith(loading: true));
-    final certifiers = await transport.certifiersOf(peerPubkey);
+    final wot = WebOfTrust.fromCertifications(
+      await transport.allCertifications(),
+      now: DateTime.now(),
+    );
+    final certifiers = wot.certifiersOf(peerPubkey);
+    final circle = wot.members(
+      seeds: {selfPubkey},
+      threshold: _circleThreshold,
+      maxDistance: _circleDistance,
+    );
     emit(state.copyWith(
       certifierCount: certifiers.length,
       iVouch: certifiers.contains(selfPubkey),
+      knownToYou: circle.contains(peerPubkey),
       loading: false,
     ));
   }

apps/app_seeds/lib/ui/chat_screen.dart

@@ -173,20 +173,31 @@ class _TrustBanner extends StatelessWidget {
       builder: (context, state) {
         final cubit = context.read<TrustCubit>();
         if (!cubit.isOnline || state.loading) return const SizedBox.shrink();
+        final known = state.knownToYou;
         return Container(
           width: double.infinity,
           color: seedPrimaryContainer.withValues(alpha: 0.5),
           padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
           child: Row(
             children: [
-              const Icon(Icons.verified_user_outlined, size: 18, color: seedGreen),
+              Icon(
+                known ? Icons.verified : Icons.verified_user_outlined,
+                size: 18,
+                color: seedGreen,
+              ),
               const SizedBox(width: 8),
               Expanded(
                 child: Text(
-                  state.certifierCount == 0
-                      ? t.trust.none
-                      : t.trust.count(n: state.certifierCount),
-                  style: const TextStyle(color: seedOnSurface, fontSize: 13),
+                  known
+                      ? t.trust.circle
+                      : state.certifierCount == 0
+                          ? t.trust.none
+                          : t.trust.count(n: state.certifierCount),
+                  style: TextStyle(
+                    color: known ? seedGreen : seedOnSurface,
+                    fontSize: 13,
+                    fontWeight: known ? FontWeight.w600 : FontWeight.w400,
+                  ),
                 ),
               ),
               TextButton(

apps/app_seeds/test/state/trust_cubit_test.dart

@@ -6,7 +6,11 @@ import 'package:tane/state/trust_cubit.dart';
 class FakeTrustTransport implements TrustTransport {
   FakeTrustTransport(this.selfId);
   final String selfId;
-  final Map<String, Set<String>> _certs = {};
+  final Map<String, Set<String>> _certs = {}; // subject -> issuers
+
+  /// Test helper: record an arbitrary issuer→subject vouch (to build a graph).
+  void addCert(String issuer, String subject) =>
+      (_certs[subject] ??= {}).add(issuer);
 
   @override
   Future<Set<String>> certifiersOf(String subjectPubkey) async =>
@@ -18,14 +22,22 @@ class FakeTrustTransport implements TrustTransport {
     Duration validity = const Duration(days: 365),
     String note = '',
   }) async =>
-      (_certs[subjectPubkey] ??= {}).add(selfId);
+      addCert(selfId, subjectPubkey);
 
   @override
   Future<void> revoke({required String subjectPubkey}) async =>
       _certs[subjectPubkey]?.remove(selfId);
 
   @override
-  Future<List<Certification>> allCertifications() async => const [];
+  Future<List<Certification>> allCertifications() async => [
+        for (final entry in _certs.entries)
+          for (final issuer in entry.value)
+            Certification(
+              issuer: issuer,
+              subject: entry.key,
+              issuedAt: DateTime(2026),
+            ),
+      ];
 
   @override
   Future<void> close() async {}
@@ -62,6 +74,23 @@ void main() {
     await cubit.close();
   });
 
+  test('a friend-of-a-friend is in your circle; a stranger is not', () async {
+    final transport = FakeTrustTransport(me)
+      ..addCert(me, 'friend') // you vouch for a friend
+      ..addCert('friend', peer) // your friend vouches for the peer
+      ..addCert('stranger', 'other'); // unrelated to you
+
+    final inCircle = TrustCubit(transport, peerPubkey: peer, selfPubkey: me);
+    await inCircle.load();
+    expect(inCircle.state.knownToYou, isTrue);
+    await inCircle.close();
+
+    final outside = TrustCubit(transport, peerPubkey: 'other', selfPubkey: me);
+    await outside.load();
+    expect(outside.state.knownToYou, isFalse);
+    await outside.close();
+  });
+
   test('never vouches for self', () async {
     final cubit =
         TrustCubit(FakeTrustTransport(me), peerPubkey: me, selfPubkey: me);