feat(plantare): surface product link + dates; spec the bilateral record

The Plantaré screen stored madeOn/dueBy/varietyId but showed none of them,
so it felt half-built. Surface what's already there (no schema change):

- watchPlantareViews() joins each commitment with its variety label
- tile shows the made-on date, a "Return by {date}" line (amber + "overdue"
  when an open promise is past due, via new seedWarning colour), the variety
  name, and taps through to /variety/:id
- add sheet gains an optional return-by date picker (createPlantare already
  took dueBy)
- variety detail shows a read-only commitments section (hidden when empty,
  no add button — honours the single hand-over door)
- i18n en/es/pt/ast; tests for the join, dueBy round-trip, tile, and section

Also specs the deferred two-sided record in docs/design/plantare-bilateral.md
(Nostr pubkey counterparty, PlantareTransport propose->accept->counter-sign,
deferred key/signature/movement columns, provenance DAG, reputation anchor),
with a faithful transcription of the paper Plantaré v0.4 (BAH-Semillero 2009,
CC-BY-SA). Cross-linked from data-model §2.7 and sharing-model §6.

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

@@ -940,6 +940,13 @@ class _Translations$plantare$es extends Translations$plantare$en {
 	@override String get openSection => 'Pendientes';
 	@override String get settledSection => 'Hechos';
 	@override String get removeConfirm => '¿Quitar este compromiso?';
+	@override String returnBy({required Object date}) => 'Devolver antes del ${date}';
+	@override String get overdue => 'vencido';
+	@override String get dueByLabel => 'Devolver antes de (opcional)';
+	@override String get dueByHint => 'Un recordatorio suave, nunca obligatorio';
+	@override String get pickDate => 'Elegir fecha';
+	@override String get clearDate => 'Quitar fecha';
+	@override String get sectionTitle => 'Compromisos';
 }
 
 // Path: handover
@@ -1890,6 +1897,13 @@ extension on TranslationsEs {
 			'plantare.openSection' => 'Pendientes',
 			'plantare.settledSection' => 'Hechos',
 			'plantare.removeConfirm' => '¿Quitar este compromiso?',
+			'plantare.returnBy' => ({required Object date}) => 'Devolver antes del ${date}',
+			'plantare.overdue' => 'vencido',
+			'plantare.dueByLabel' => 'Devolver antes de (opcional)',
+			'plantare.dueByHint' => 'Un recordatorio suave, nunca obligatorio',
+			'plantare.pickDate' => 'Elegir fecha',
+			'plantare.clearDate' => 'Quitar fecha',
+			'plantare.sectionTitle' => 'Compromisos',
 			'handover.title' => 'Di o recibí semillas',
 			'handover.help' => 'Un regalo, un trueque o una venta: apúntalo, con promesa de devolver semilla o sin ella.',
 			'handover.iGave' => 'Di semillas',
@@ -1909,6 +1923,8 @@ extension on TranslationsEs {
 			'sale.iBought' => 'Compré',
 			'sale.direction' => '¿Vendes o compras?',
 			'sale.counterparty' => '¿Con quién?',
+			_ => null,
+		} ?? switch (path) {
 			'sale.counterpartyHint' => 'Una persona o un colectivo (opcional)',
 			'sale.amount' => 'Importe',
 			'sale.currency' => 'Moneda',
@@ -1916,8 +1932,6 @@ extension on TranslationsEs {
 			'sale.hours' => 'horas',
 			'sale.note' => 'Nota (opcional)',
 			'sale.save' => 'Guardar',
-			_ => null,
-		} ?? switch (path) {
 			'sale.delete' => 'Quitar',
 			'sale.removeConfirm' => '¿Quitar esta venta?',
 			'legal.title' => 'Privacidad y normas',