feat(offers): asking price on lots, published with sale offers (schema v11)

The data model always meant sale offers to carry an informational price
(data-model §2.8, sharing-model §4.4); with offer state collapsed onto
the Lot, the price lives there. Null amount on a sell lot = 'to be
agreed' — the NIP-99 event simply omits the price tag.

- schema v11: Lots.price_amount/price_currency, guarded migration,
  schema dump + generated schema_v11 for the round-trip test
- ShareableLot/VarietyLot carry the price (sell-only in shareableLots);
  addLot/updateLot persist it and clear it when the lot leaves sale
- OffersCubit.publishLots forwards it (outbox flush picks it up free)
- lot sheet: price + currency inputs revealed only on 'For sale', with
  the €/Ğ1/hours quick-picks extracted to a shared CurrencyQuickPicks
  widget (reused by the sale sheet)
- backup JSON round-trips the new columns
- i18n share.price/priceHint in en/es/pt/ast

apps/app_seeds/test/data/shareable_lots_test.dart

@@ -40,4 +40,71 @@ void main() {
     final lots = await repo.shareableLots();
     expect(lots.where((l) => l.lotId == privateId), isEmpty);
   });
+
+  test('sell lots expose their asking price; other statuses never do',
+      () async {
+    final repo = newTestRepository(db);
+    final varietyId = await repo.addQuickVariety(label: 'Calabaza');
+    final sellId = await repo.addLot(
+      varietyId: varietyId,
+      offerStatus: OfferStatus.sell,
+      priceAmount: 3.5,
+      priceCurrency: 'Ğ1',
+    );
+    // Price passed on a gift lot is dropped, not stored.
+    final giftId = await repo.addLot(
+      varietyId: varietyId,
+      offerStatus: OfferStatus.shared,
+      priceAmount: 99,
+      priceCurrency: '€',
+    );
+
+    final lots = await repo.shareableLots();
+    final sell = lots.singleWhere((l) => l.lotId == sellId);
+    expect(sell.priceAmount, 3.5);
+    expect(sell.priceCurrency, 'Ğ1');
+    final gift = lots.singleWhere((l) => l.lotId == giftId);
+    expect(gift.priceAmount, isNull);
+    expect(gift.priceCurrency, isNull);
+  });
+
+  test('a sell lot without amount is "to be agreed" — shareable, no price',
+      () async {
+    final repo = newTestRepository(db);
+    final varietyId = await repo.addQuickVariety(label: 'Lechuga');
+    final sellId = await repo.addLot(
+      varietyId: varietyId,
+      offerStatus: OfferStatus.sell,
+    );
+
+    final lots = await repo.shareableLots();
+    final sell = lots.singleWhere((l) => l.lotId == sellId);
+    expect(sell.priceAmount, isNull);
+  });
+
+  test('moving a lot out of sale clears its stored price', () async {
+    final repo = newTestRepository(db);
+    final varietyId = await repo.addQuickVariety(label: 'Haba');
+    final lotId = await repo.addLot(
+      varietyId: varietyId,
+      offerStatus: OfferStatus.sell,
+      priceAmount: 2,
+      priceCurrency: '€',
+    );
+
+    await repo.updateLot(
+      lotId: lotId,
+      type: LotType.seed,
+      offerStatus: OfferStatus.shared,
+      // Price args still sent by the form; must be ignored off-sale.
+      priceAmount: 2,
+      priceCurrency: '€',
+    );
+
+    final detail = await repo.watchVariety(varietyId).first;
+    final lot = detail!.lots.singleWhere((l) => l.id == lotId);
+    expect(lot.priceAmount, isNull);
+    expect(lot.priceCurrency, isNull);
+    expect(lot.offerStatus, OfferStatus.shared);
+  });
 }

apps/app_seeds/test/db/migration_test.dart

@@ -11,19 +11,19 @@ void main() {
     verifier = SchemaVerifier(GeneratedHelper());
   });
 
-  test('freshly created database matches the exported schema v10', () async {
-    final schema = await verifier.schemaAt(10);
+  test('freshly created database matches the exported schema v11', () async {
+    final schema = await verifier.schemaAt(11);
     final db = AppDatabase(schema.newConnection());
-    await verifier.migrateAndValidate(db, 10);
+    await verifier.migrateAndValidate(db, 11);
     await db.close();
   });
 
-  // Every historical version upgrades cleanly to the current schema (v10).
-  for (var from = 1; from <= 9; from++) {
-    test('upgrades v$from → v10 and matches the fresh schema', () async {
+  // Every historical version upgrades cleanly to the current schema (v11).
+  for (var from = 1; from <= 10; from++) {
+    test('upgrades v$from → v11 and matches the fresh schema', () async {
       final connection = await verifier.startAt(from);
       final db = AppDatabase(connection);
-      await verifier.migrateAndValidate(db, 10);
+      await verifier.migrateAndValidate(db, 11);
       await db.close();
     });
   }

apps/app_seeds/test/db/schema/schema.dart

@@ -14,6 +14,7 @@ import 'schema_v7.dart' as v7;
 import 'schema_v8.dart' as v8;
 import 'schema_v9.dart' as v9;
 import 'schema_v10.dart' as v10;
+import 'schema_v11.dart' as v11;
 
 class GeneratedHelper implements SchemaInstantiationHelper {
   @override
@@ -39,10 +40,12 @@ class GeneratedHelper implements SchemaInstantiationHelper {
         return v9.DatabaseAtV9(db);
       case 10:
         return v10.DatabaseAtV10(db);
+      case 11:
+        return v11.DatabaseAtV11(db);
       default:
         throw MissingSchemaException(version, versions);
     }
   }
 
-  static const versions = const [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+  static const versions = const [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
 }

apps/app_seeds/test/state/offers_cubit_test.dart

@@ -294,6 +294,43 @@ void main() {
       await cubit.close();
     });
 
+    test('publishLots carries the lot asking price on sale offers', () async {
+      final transport = FakeOfferTransport();
+      final cubit = OffersCubit(transport);
+      await cubit.publishLots(
+        const [
+          ShareableLot(
+            lotId: 'lot-sale',
+            varietyId: 'var-1',
+            summary: 'Tomate',
+            offerStatus: OfferStatus.sell,
+            priceAmount: 3.5,
+            priceCurrency: 'Ğ1',
+          ),
+          // "To be agreed": sale without a figure publishes without a price.
+          ShareableLot(
+            lotId: 'lot-negotiable',
+            varietyId: 'var-2',
+            summary: 'Judía',
+            offerStatus: OfferStatus.sell,
+          ),
+        ],
+        authorPubkeyHex: 'ab' * 32,
+        areaGeohash: 'sp3e9',
+      );
+
+      await cubit.discover('sp3');
+      await pumpEventQueue();
+      final sale = cubit.state.offers.singleWhere((o) => o.id == 'lot-sale');
+      expect(sale.type, OfferType.sale);
+      expect(sale.priceAmount, 3.5);
+      expect(sale.priceCurrency, 'Ğ1');
+      final negotiable =
+          cubit.state.offers.singleWhere((o) => o.id == 'lot-negotiable');
+      expect(negotiable.priceAmount, isNull);
+      await cubit.close();
+    });
+
     test('publishLots embeds an inline thumbnail data-URI on the offer',
         () async {
       final transport = FakeOfferTransport();