feat(plantare): usable UI — commitments screen, add sheet, entry points

The reproduction-commitment (Plantare) UI, local-first and plain-spoken:
- A Plantares screen (drawer entry, /plantares) listing your commitments,
  grouped Open / Done, with a big 'mark returned', a menu (let it go / reopen
  / remove) and an empty-state that explains what a Plantare is.
- An add sheet (scrollable): a two-choice 'who reproduces & returns' (I return
  / owed to me), an optional 'with whom', an optional 'what comes back' in the
  grower's own words, and a note. No sale, no currency — a promise.
- Reachable from a seed too: an 'Add a commitment' action on the variety
  detail, pre-attached to that variety.
- i18n en/es/pt/ast (human words: 'Plantare' + a plain explanation).

Added the Plantares screen to the small-phone overflow guard (18 cases green).

apps/app_seeds/test/ui/small_screen_overflow_test.dart

@@ -15,6 +15,7 @@ import 'package:tane/ui/home_screen.dart';
 import 'package:tane/ui/intro_screen.dart';
 import 'package:tane/ui/inventory_list_screen.dart';
 import 'package:tane/ui/market_screen.dart';
+import 'package:tane/ui/plantares_screen.dart';
 import 'package:tane/ui/profile_screen.dart';
 import 'package:tane/ui/settings_screen.dart';
 
@@ -236,6 +237,27 @@ void main() {
     await disposeTree(tester);
   });
 
+  testWidgets('the Plantares screen (with a commitment) fits a small screen',
+      (tester) async {
+    final db = newTestDatabase();
+    addTearDown(db.close);
+    final repo = newTestRepository(db);
+    await repo.createPlantare(
+      direction: PlantareDirection.iReturn,
+      counterparty: 'Colectivo semillero de la comarca',
+      owedDescription: 'un puñado la próxima temporada, si germina bien',
+    );
+    await pumpSmall(
+      tester,
+      wrapScreen(
+        repository: repo,
+        locale: AppLocale.es,
+        child: const PlantaresScreen(),
+      ),
+    );
+    await disposeTree(tester);
+  });
+
   // NOTE: the variety-detail screen is deliberately NOT overflow-checked here.
   // It reports a ~2px overflow on a RenderFlex that is already DISPOSED/DEFUNCT
   // — a transient stale frame while its cubit's Drift stream rebuilds during