feat(plantare): reproduction-commitment data layer (schema v9)

The Plantare — a promise to reproduce seed and return some (data-model §2.7,
the seed-domain Pledge with return_kind=similar). NOT a sale. Local-first
v1: your honest ledger of commitments (from/to a person by name); the
bilateral signed cross-party form is a later social-layer phase.

- New Plantares table (SyncColumns): varietyId, direction (iReturn/owedToMe),
  counterparty, owedDescription, madeOn, dueBy, status (open/returned/
  forgiven), settledOn, note. schemaVersion 8 -> 9 with a guarded createTable
  migration; schema exported + migration-test helper regenerated.
- VarietyRepository: createPlantare / watchPlantares / watchPlantaresForVariety
  / setPlantareStatus / deletePlantare (soft-delete, CRDT-stamped).
- Included in backups + sync: InventorySnapshot + JSON codec (round-trips
  isDeleted) + exportInventory/exportForSync/importInventory, so commitments
  survive restore and replicate LWW like every other row.

Tests: v1..v8 -> v9 migration + fresh v9; repo create/list/settle/reopen/
delete; and a backup round-trip preserving a commitment. 13 green.

UI (detail section + Plantares screen) follows.

apps/app_seeds/lib/db/tables.dart

@@ -173,6 +173,45 @@ class Attachments extends Table with SyncColumns {
   IntColumn get sortOrder => integer().withDefault(const Constant(0))();
 }
 
+/// A Plantare — a REPRODUCTION commitment (data-model §2.7), the seed-domain
+/// name for the generic `Pledge` (`return_kind = similar`). Seed changes hands
+/// and the receiver promises to grow it out and return some. NOT a sale.
+///
+/// Local-first v1: your own honest ledger of commitments (from/to a person by
+/// name). The bilateral, cryptographically SIGNED, cross-party form
+/// (debtor/creditor keys + both signatures, tied to a shared `Movement`) is a
+/// later social-layer phase — those columns are deferred, not invented now.
+class Plantares extends Table with SyncColumns {
+  /// The seed the commitment is about — what gets reproduced. Nullable so a
+  /// commitment can be jotted before it's linked to a catalogued variety.
+  TextColumn get varietyId => text().nullable()(); // → Variety
+
+  /// Whose promise it is (I return / owed to me).
+  TextColumn get direction => textEnum<PlantareDirection>()();
+
+  /// The other party as a human name (v1). A key/Party link arrives with the
+  /// signed cross-party form.
+  TextColumn get counterparty => text().nullable()();
+
+  /// What's promised back, in the grower's own words
+  /// ("un puñado la próxima temporada").
+  TextColumn get owedDescription => text().nullable()();
+
+  /// When the promise was made (ms since epoch).
+  IntColumn get madeOn => integer()();
+
+  /// Optional return-by date (ms since epoch) — a gentle reminder, not a deadline.
+  IntColumn get dueBy => integer().nullable()();
+
+  TextColumn get status =>
+      textEnum<PlantareStatus>().withDefault(const Constant('open'))();
+
+  /// When it was returned or forgiven (ms since epoch).
+  IntColumn get settledOn => integer().nullable()();
+
+  TextColumn get note => text().nullable()();
+}
+
 /// Any pasted URL (Wikipedia, forum…). Polymorphic parent.
 class ExternalLinks extends Table with SyncColumns {
   TextColumn get parentType => textEnum<ParentType>()();