feat(db): lot presentation + attachment sort order (schema v4→v5)

Expand LotType from {seed, plant} to six append-only forms (seed,
seedling, plant, tree, bulb, cutting) and add an optional Presentation
attribute (pot/tray/plug/bareRoot/rootBall) kept separate from quantity
so 'how many' and 'in what packaging' never conflate.

Add attachments.sortOrder so the cover photo is the lowest-ordered one,
enabling reordering from the full-screen viewer. Expand QuantityKind
with the new plant-aware forms.

Migrations are additive (v1→v5 all covered by migration_test); enum
values are stored by name and appended only, keeping CRDT sync safe.

apps/app_seeds/lib/data/variety_repository.dart

@@ -67,6 +67,7 @@ class VarietyLot extends Equatable {
     this.harvestYear,
     this.harvestMonth,
     this.quantity,
+    this.presentation,
     this.storageLocation,
     this.germinationTests = const [],
   });
@@ -78,6 +79,9 @@ class VarietyLot extends Equatable {
   /// Optional harvest month (1..12). Only meaningful when [harvestYear] is set.
   final int? harvestMonth;
   final Quantity? quantity;
+
+  /// How living material is packaged (pot, tray, bare-root…); null for seeds.
+  final Presentation? presentation;
   final String? storageLocation;
   final List<GerminationEntry> germinationTests;
 
@@ -92,6 +96,7 @@ class VarietyLot extends Equatable {
     harvestYear,
     harvestMonth,
     quantity,
+    presentation,
     storageLocation,
     germinationTests,
   ];
@@ -252,13 +257,18 @@ class VarietyRepository {
   ) async {
     if (varietyIds.isEmpty) return const {};
     final rows =
-        await (_db.select(_db.attachments)..where(
-              (a) =>
-                  a.parentId.isIn(varietyIds) &
-                  a.parentType.equalsValue(ParentType.variety) &
-                  a.kind.equalsValue(AttachmentKind.photo) &
-                  a.isDeleted.equals(false),
-            ))
+        await (_db.select(_db.attachments)
+              ..where(
+                (a) =>
+                    a.parentId.isIn(varietyIds) &
+                    a.parentType.equalsValue(ParentType.variety) &
+                    a.kind.equalsValue(AttachmentKind.photo) &
+                    a.isDeleted.equals(false),
+              )
+              ..orderBy([
+                (a) => OrderingTerm(expression: a.sortOrder),
+                (a) => OrderingTerm(expression: a.createdAt),
+              ]))
             .get();
     final byVariety = <String, Uint8List>{};
     for (final row in rows) {
@@ -431,7 +441,10 @@ class VarietyRepository {
                     a.kind.equalsValue(AttachmentKind.photo) &
                     a.isDeleted.equals(false),
               )
-              ..orderBy([(a) => OrderingTerm(expression: a.createdAt)]))
+              ..orderBy([
+                (a) => OrderingTerm(expression: a.sortOrder),
+                (a) => OrderingTerm(expression: a.createdAt),
+              ]))
             .get();
 
     final links =
@@ -527,6 +540,7 @@ class VarietyRepository {
     int? harvestYear,
     int? harvestMonth,
     Quantity? quantity,
+    Presentation? presentation,
     String? storageLocation,
   }) async {
     final (created, updated) = _stamp();
@@ -546,6 +560,7 @@ class VarietyRepository {
             quantityKind: Value(quantity?.kind.name),
             quantityPrecise: Value(quantity?.count?.toDouble()),
             quantityLabel: Value(quantity?.label),
+            presentation: Value(presentation),
             storageLocation: Value(storageLocation),
           ),
         );
@@ -560,6 +575,7 @@ class VarietyRepository {
     int? harvestYear,
     int? harvestMonth,
     Quantity? quantity,
+    Presentation? presentation,
     String? storageLocation,
   }) async {
     final (_, updated) = _stamp();
@@ -571,6 +587,7 @@ class VarietyRepository {
         quantityKind: Value(quantity?.kind.name),
         quantityPrecise: Value(quantity?.count?.toDouble()),
         quantityLabel: Value(quantity?.label),
+        presentation: Value(presentation),
         storageLocation: Value(storageLocation),
         updatedAt: Value(updated),
         lastAuthor: Value(nodeId),
@@ -666,6 +683,34 @@ class VarietyRepository {
     );
   }
 
+  /// Makes [attachmentId] the cover (preferred) attachment of [varietyId] by
+  /// giving it a [sortOrder] below every current sibling. The cover is what the
+  /// inventory list shows as the avatar and the detail gallery shows first.
+  Future<void> setPreferredPhoto(String varietyId, String attachmentId) async {
+    final siblings =
+        await (_db.select(_db.attachments)..where(
+              (a) =>
+                  a.parentId.equals(varietyId) &
+                  a.parentType.equalsValue(ParentType.variety) &
+                  a.isDeleted.equals(false),
+            ))
+            .get();
+    var minOrder = 0;
+    for (final a in siblings) {
+      if (a.sortOrder < minOrder) minOrder = a.sortOrder;
+    }
+    final (_, updated) = _stamp();
+    await (_db.update(
+      _db.attachments,
+    )..where((a) => a.id.equals(attachmentId))).write(
+      AttachmentsCompanion(
+        sortOrder: Value(minOrder - 1),
+        updatedAt: Value(updated),
+        lastAuthor: Value(nodeId),
+      ),
+    );
+  }
+
   /// Adds an external link (URL, optional title) to a variety. Returns its id.
   Future<String> addExternalLink(
     String varietyId,
@@ -756,6 +801,7 @@ class VarietyRepository {
       type: l.type,
       harvestYear: l.harvestYear,
       harvestMonth: l.harvestMonth,
+      presentation: l.presentation,
       storageLocation: l.storageLocation,
       germinationTests: germinationTests,
       quantity: hasQuantity