feat(block2): offline outbox — share now, publish when connected

Sender-side offline delivery hardening.
- OfferOutbox: a keystore-backed (no plaintext) queue of lot ids to publish
  later. Stores ids, not offers, so on flush each offer is rebuilt from the
  lot's CURRENT state — an offline edit is respected, a deleted lot drops out.
- flushOutbox(): on reconnect, republishes queued lots and clears them (no-op
  offline; drops ids whose lot is gone).
- Market screen: sharing offline parks the lots ('we'll share these when you're
  connected'); opening the market online auto-flushes the queue first.
- Wired via DI + TaneApp(outbox); i18n en/es/pt.

Tests: 4 outbox + 3 flush + market UI, 20 green. Analyzer clean for new code.

apps/app_seeds/lib/app.dart

@@ -8,6 +8,7 @@ import 'data/species_repository.dart';
 import 'data/variety_repository.dart';
 import 'i18n/strings.g.dart';
 import 'services/coarse_location.dart';
+import 'services/offer_outbox.dart';
 import 'services/onboarding_store.dart';
 import 'services/social_service.dart';
 import 'services/social_settings.dart';
@@ -33,6 +34,7 @@ class TaneApp extends StatelessWidget {
     this.social,
     this.socialSettings,
     this.location,
+    this.outbox,
     this.showIntro = false,
     super.key,
   }) : _router = _buildRouter(
@@ -42,6 +44,7 @@ class TaneApp extends StatelessWidget {
           social,
           socialSettings,
           location,
+          outbox,
         );
 
   final VarietyRepository repository;
@@ -55,6 +58,9 @@ class TaneApp extends StatelessWidget {
 
   /// Optional device-location source for the market's "use my location".
   final CoarseLocationProvider? location;
+
+  /// Optional offline outbox for the market's "share my seeds".
+  final OfferOutbox? outbox;
   final bool showIntro;
   final GoRouter _router;
 
@@ -65,6 +71,7 @@ class TaneApp extends StatelessWidget {
     SocialService? social,
     SocialSettings? socialSettings,
     CoarseLocationProvider? location,
+    OfferOutbox? outbox,
   ) {
     return GoRouter(
       initialLocation: showIntro ? '/intro' : '/',
@@ -81,6 +88,7 @@ class TaneApp extends StatelessWidget {
               social: social,
               settings: socialSettings,
               location: location,
+              outbox: outbox,
             ),
           ),
         GoRoute(

apps/app_seeds/lib/di/injector.dart

@@ -24,6 +24,7 @@ import '../services/ocr/tesseract_label_extractor.dart';
 import '../services/onboarding_store.dart';
 import '../services/recovery_sheet_service.dart';
 import '../services/share_catalog_service.dart';
+import '../services/offer_outbox.dart';
 import '../services/social_service.dart';
 import '../services/social_settings.dart';
 
@@ -85,6 +86,7 @@ Future<void> configureDependencies() async {
     ..registerSingleton<OnboardingStore>(OnboardingStore(secretStore))
     ..registerSingleton<SocialService>(socialService)
     ..registerSingleton<SocialSettings>(SocialSettings(secretStore))
+    ..registerSingleton<OfferOutbox>(OfferOutbox(secretStore))
     ..registerSingleton<ExportImportService>(
       ExportImportService(
         repository: varietyRepository,

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

@@ -353,6 +353,7 @@
     "sharedCount": "Shared {n} seeds nearby",
     "nothingToShare": "Mark some seeds to give, swap or sell first",
     "useLocation": "Use my approximate location",
-    "locationFailed": "Couldn't get your location"
+    "locationFailed": "Couldn't get your location",
+    "queued": "Saved — we'll share these when you're connected"
   }
 }

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

@@ -353,6 +353,7 @@
     "sharedCount": "Compartidas {n} semillas",
     "nothingToShare": "Marca antes algunas semillas para regalar, cambiar o vender",
     "useLocation": "Usar mi ubicación aproximada",
-    "locationFailed": "No se pudo obtener tu ubicación"
+    "locationFailed": "No se pudo obtener tu ubicación",
+    "queued": "Guardado — las compartiremos cuando tengas conexión"
   }
 }

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

@@ -349,6 +349,7 @@
     "sharedCount": "Partilhadas {n} sementes",
     "nothingToShare": "Marca primeiro algumas sementes para dar, trocar ou vender",
     "useLocation": "Usar a minha localização aproximada",
-    "locationFailed": "Não foi possível obter a tua localização"
+    "locationFailed": "Não foi possível obter a tua localização",
+    "queued": "Guardado — vamos partilhá-las quando tiveres ligação"
   }
 }

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

@@ -4,9 +4,9 @@
 /// To regenerate, run: `dart run slang`
 ///
 /// Locales: 3
-/// Strings: 944 (314 per locale)
+/// Strings: 947 (315 per locale)
 ///
-/// Built on 2026-07-10 at 08:25 UTC
+/// Built on 2026-07-10 at 08:44 UTC
 
 // coverage:ignore-file
 // ignore_for_file: type=lint, unused_import

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

@@ -1120,6 +1120,9 @@ class Translations$market$en {
 
 	/// en: 'Couldn't get your location'
 	String get locationFailed => 'Couldn\'t get your location';
+
+	/// en: 'Saved — we'll share these when you're connected'
+	String get queued => 'Saved — we\'ll share these when you\'re connected';
 }
 
 // Path: intro.slides
@@ -1895,6 +1898,7 @@ extension on Translations {
 			'market.nothingToShare' => 'Mark some seeds to give, swap or sell first',
 			'market.useLocation' => 'Use my approximate location',
 			'market.locationFailed' => 'Couldn\'t get your location',
+			'market.queued' => 'Saved — we\'ll share these when you\'re connected',
 			_ => null,
 		};
 	}

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

@@ -624,6 +624,7 @@ class _Translations$market$es extends Translations$market$en {
 	@override String get nothingToShare => 'Marca antes algunas semillas para regalar, cambiar o vender';
 	@override String get useLocation => 'Usar mi ubicación aproximada';
 	@override String get locationFailed => 'No se pudo obtener tu ubicación';
+	@override String get queued => 'Guardado — las compartiremos cuando tengas conexión';
 }
 
 // Path: intro.slides
@@ -1283,6 +1284,7 @@ extension on TranslationsEs {
 			'market.nothingToShare' => 'Marca antes algunas semillas para regalar, cambiar o vender',
 			'market.useLocation' => 'Usar mi ubicación aproximada',
 			'market.locationFailed' => 'No se pudo obtener tu ubicación',
+			'market.queued' => 'Guardado — las compartiremos cuando tengas conexión',
 			_ => null,
 		};
 	}

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

@@ -620,6 +620,7 @@ class _Translations$market$pt extends Translations$market$en {
 	@override String get nothingToShare => 'Marca primeiro algumas sementes para dar, trocar ou vender';
 	@override String get useLocation => 'Usar a minha localização aproximada';
 	@override String get locationFailed => 'Não foi possível obter a tua localização';
+	@override String get queued => 'Guardado — vamos partilhá-las quando tiveres ligação';
 }
 
 // Path: intro.slides
@@ -1275,6 +1276,7 @@ extension on TranslationsPt {
 			'market.nothingToShare' => 'Marca primeiro algumas sementes para dar, trocar ou vender',
 			'market.useLocation' => 'Usar a minha localização aproximada',
 			'market.locationFailed' => 'Não foi possível obter a tua localização',
+			'market.queued' => 'Guardado — vamos partilhá-las quando tiveres ligação',
 			_ => null,
 		};
 	}

apps/app_seeds/lib/main.dart

@@ -6,6 +6,7 @@ import 'data/variety_repository.dart';
 import 'di/injector.dart';
 import 'i18n/strings.g.dart';
 import 'services/coarse_location.dart';
+import 'services/offer_outbox.dart';
 import 'services/onboarding_store.dart';
 import 'services/social_service.dart';
 import 'services/social_settings.dart';
@@ -24,6 +25,7 @@ Future<void> main() async {
         social: getIt<SocialService>(),
         socialSettings: getIt<SocialSettings>(),
         location: const GeolocatorCoarseLocation(),
+        outbox: getIt<OfferOutbox>(),
         showIntro: !await onboarding.introSeen(),
       ),
     ),

apps/app_seeds/lib/services/offer_outbox.dart

@@ -0,0 +1,37 @@
+import '../security/secret_store.dart';
+
+/// A durable "to publish when connected" queue of lot ids. When sharing is
+/// attempted offline, the lot ids are parked here (keystore-backed, so no
+/// plaintext at rest) and flushed once a relay is reachable — offline delivery
+/// for the sender side.
+///
+/// We store lot ids, not serialized offers: on flush the offer is rebuilt from
+/// the lot's current state, so an edit made while offline is respected and a
+/// since-deleted lot simply drops out.
+class OfferOutbox {
+  OfferOutbox(this._store);
+
+  final SecretStore _store;
+  static const _key = 'tane.social.outbox';
+
+  /// Lot ids waiting to be published.
+  Future<Set<String>> pending() async {
+    final raw = await _store.read(_key);
+    if (raw == null || raw.isEmpty) return <String>{};
+    return raw.split('\n').where((s) => s.isNotEmpty).toSet();
+  }
+
+  Future<void> enqueue(Iterable<String> lotIds) async {
+    final next = await pending()..addAll(lotIds);
+    await _write(next);
+  }
+
+  Future<void> remove(Iterable<String> lotIds) async {
+    final next = await pending()..removeAll(lotIds.toSet());
+    await _write(next);
+  }
+
+  Future<void> clear() => _store.write(_key, '');
+
+  Future<void> _write(Set<String> ids) => _store.write(_key, ids.join('\n'));
+}

apps/app_seeds/lib/state/offers_cubit.dart

@@ -6,6 +6,7 @@ import 'package:flutter_bloc/flutter_bloc.dart';
 
 import '../data/variety_repository.dart';
 import '../services/offer_mapper.dart';
+import '../services/offer_outbox.dart';
 import '../services/social_service.dart';
 import '../services/social_settings.dart';
 
@@ -178,3 +179,31 @@ Future<OffersCubit> createOffersCubit(
     return OffersCubit(null); // offline / no relay reachable
   }
 }
+
+/// Publishes any queued (offline-parked) lots now that we're online, then clears
+/// them from the [outbox]. Rebuilds each offer from the lot's CURRENT state, so
+/// since-deleted or now-private lots simply drop out. Returns how many published.
+Future<int> flushOutbox({
+  required OfferOutbox outbox,
+  required OffersCubit cubit,
+  required List<ShareableLot> shareableLots,
+  required String authorPubkeyHex,
+  required String areaGeohash,
+}) async {
+  if (!cubit.isOnline || areaGeohash.isEmpty) return 0;
+  final queued = await outbox.pending();
+  if (queued.isEmpty) return 0;
+  final toPublish =
+      shareableLots.where((l) => queued.contains(l.lotId)).toList();
+  var published = 0;
+  if (toPublish.isNotEmpty) {
+    published = await cubit.publishLots(
+      toPublish,
+      authorPubkeyHex: authorPubkeyHex,
+      areaGeohash: areaGeohash,
+    );
+  }
+  // Clear everything attempted (or gone) so we don't loop on it.
+  await outbox.remove(queued);
+  return published;
+}

apps/app_seeds/lib/ui/market_screen.dart

@@ -5,6 +5,7 @@ import 'package:flutter_bloc/flutter_bloc.dart';
 import '../data/variety_repository.dart';
 import '../i18n/strings.g.dart';
 import '../services/coarse_location.dart';
+import '../services/offer_outbox.dart';
 import '../services/social_service.dart';
 import '../services/social_settings.dart';
 import '../state/offers_cubit.dart';
@@ -18,6 +19,7 @@ class MarketScreen extends StatefulWidget {
     required this.social,
     required this.settings,
     this.location,
+    this.outbox,
     super.key,
   });
 
@@ -28,6 +30,10 @@ class MarketScreen extends StatefulWidget {
   /// null (tests, or a platform without it) the shortcut is hidden.
   final CoarseLocationProvider? location;
 
+  /// Optional offline outbox: parks shares attempted with no network and flushes
+  /// them on reconnect. Null in tests → sharing offline is simply a no-op.
+  final OfferOutbox? outbox;
+
   @override
   State<MarketScreen> createState() => _MarketScreenState();
 }
@@ -43,6 +49,10 @@ class _MarketScreenState extends State<MarketScreen> {
   }
 
   Future<void> _init() async {
+    // Only needed to flush the outbox; read here (while mounted) to avoid using
+    // context across the awaits below. Null when there's no outbox (e.g. tests).
+    final repo =
+        widget.outbox != null ? context.read<VarietyRepository>() : null;
     setState(() => _loading = true);
     final cubit = await createOffersCubit(widget.social, widget.settings);
     final area = await widget.settings.areaGeohash();
@@ -56,7 +66,20 @@ class _MarketScreenState extends State<MarketScreen> {
       _loading = false;
     });
     await previous?.close();
-    if (area.isNotEmpty && cubit.isOnline) await cubit.discover(area);
+    if (area.isNotEmpty && cubit.isOnline) {
+      // Flush anything parked while offline, then show what's out there.
+      final outbox = widget.outbox;
+      if (outbox != null && repo != null) {
+        await flushOutbox(
+          outbox: outbox,
+          cubit: cubit,
+          shareableLots: await repo.shareableLots(),
+          authorPubkeyHex: widget.social.publicKeyHex,
+          areaGeohash: area,
+        );
+      }
+      if (mounted) await cubit.discover(area);
+    }
   }
 
   Future<void> _openConfig() async {
@@ -73,7 +96,7 @@ class _MarketScreenState extends State<MarketScreen> {
   /// coarse area. Prompts for setup when the area isn't set.
   Future<void> _shareMine() async {
     final cubit = _cubit;
-    if (cubit == null || !cubit.isOnline) return;
+    if (cubit == null) return;
     final repo = context.read<VarietyRepository>();
     final messenger = ScaffoldMessenger.of(context);
     final t = context.t;
@@ -89,12 +112,23 @@ class _MarketScreenState extends State<MarketScreen> {
       messenger.showSnackBar(SnackBar(content: Text(t.market.nothingToShare)));
       return;
     }
+    final ids = lots.map((l) => l.lotId).toList();
+
+    // Offline: park it and tell the person we'll share it later.
+    if (!cubit.isOnline) {
+      await widget.outbox?.enqueue(ids);
+      if (!mounted) return;
+      messenger.showSnackBar(SnackBar(content: Text(t.market.queued)));
+      return;
+    }
+
     final count = await cubit.publishLots(
       lots,
       authorPubkeyHex: widget.social.publicKeyHex,
       areaGeohash: area,
     );
     if (!mounted) return;
+    await widget.outbox?.remove(ids); // published now, so unpark any duplicates
     messenger.showSnackBar(SnackBar(content: Text(t.market.sharedCount(n: count))));
     await cubit.discover(area); // refresh — now including the just-shared lots
   }
@@ -113,7 +147,7 @@ class _MarketScreenState extends State<MarketScreen> {
       appBar: AppBar(
         title: Text(t.market.title),
         actions: [
-          if (cubit != null && cubit.isOnline)
+          if (cubit != null && (cubit.isOnline || widget.outbox != null))
             IconButton(
               key: const Key('market.shareMine'),
               icon: const Icon(Icons.ios_share_outlined),

apps/app_seeds/test/services/offer_outbox_test.dart

@@ -0,0 +1,31 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:tane/services/offer_outbox.dart';
+
+import '../support/test_support.dart';
+
+void main() {
+  late OfferOutbox outbox;
+  setUp(() => outbox = OfferOutbox(InMemorySecretStore()));
+
+  test('starts empty', () async {
+    expect(await outbox.pending(), isEmpty);
+  });
+
+  test('enqueue adds ids; it is a set (no duplicates)', () async {
+    await outbox.enqueue(['a', 'b']);
+    await outbox.enqueue(['b', 'c']);
+    expect(await outbox.pending(), {'a', 'b', 'c'});
+  });
+
+  test('remove drops the given ids', () async {
+    await outbox.enqueue(['a', 'b', 'c']);
+    await outbox.remove(['b']);
+    expect(await outbox.pending(), {'a', 'c'});
+  });
+
+  test('clear empties it', () async {
+    await outbox.enqueue(['a', 'b']);
+    await outbox.clear();
+    expect(await outbox.pending(), isEmpty);
+  });
+}

apps/app_seeds/test/state/offers_cubit_test.dart

@@ -5,8 +5,11 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:tane/data/variety_repository.dart';
 import 'package:tane/db/enums.dart';
 import 'package:tane/services/offer_mapper.dart';
+import 'package:tane/services/offer_outbox.dart';
 import 'package:tane/state/offers_cubit.dart';
 
+import '../support/test_support.dart';
+
 /// In-memory [OfferTransport] for tests: addressable by id, discover matches by
 /// geohash prefix. No relay, no network.
 class FakeOfferTransport implements OfferTransport {
@@ -196,6 +199,63 @@ void main() {
       await noArea.close();
     });
 
+    test('flushOutbox publishes queued lots, then clears them', () async {
+      final outbox = OfferOutbox(InMemorySecretStore());
+      await outbox.enqueue(['lot-1', 'lot-2']);
+      final cubit = OffersCubit(FakeOfferTransport());
+      final count = await flushOutbox(
+        outbox: outbox,
+        cubit: cubit,
+        shareableLots: const [
+          ShareableLot(
+              lotId: 'lot-1', summary: 'Tomate', offerStatus: OfferStatus.shared),
+          ShareableLot(
+              lotId: 'lot-2',
+              summary: 'Judía',
+              offerStatus: OfferStatus.exchange),
+          ShareableLot(
+              lotId: 'lot-3', summary: 'Otro', offerStatus: OfferStatus.shared),
+        ],
+        authorPubkeyHex: 'ab' * 32,
+        areaGeohash: 'sp3e9',
+      );
+      expect(count, 2);
+      expect(await outbox.pending(), isEmpty);
+      await cubit.close();
+    });
+
+    test('flushOutbox offline keeps the queue for later', () async {
+      final outbox = OfferOutbox(InMemorySecretStore());
+      await outbox.enqueue(['lot-1']);
+      final cubit = OffersCubit(null); // offline
+      final count = await flushOutbox(
+        outbox: outbox,
+        cubit: cubit,
+        shareableLots: const [],
+        authorPubkeyHex: 'ab' * 32,
+        areaGeohash: 'sp3e9',
+      );
+      expect(count, 0);
+      expect(await outbox.pending(), {'lot-1'});
+      await cubit.close();
+    });
+
+    test('flushOutbox drops queued lots that no longer exist', () async {
+      final outbox = OfferOutbox(InMemorySecretStore());
+      await outbox.enqueue(['gone']);
+      final cubit = OffersCubit(FakeOfferTransport());
+      final count = await flushOutbox(
+        outbox: outbox,
+        cubit: cubit,
+        shareableLots: const [],
+        authorPubkeyHex: 'ab' * 32,
+        areaGeohash: 'sp3e9',
+      );
+      expect(count, 0);
+      expect(await outbox.pending(), isEmpty);
+      await cubit.close();
+    });
+
     test('offline (no transport): degrades gracefully, never throws', () async {
       final cubit = OffersCubit(null);
       expect(cubit.isOnline, isFalse);