feat(train): a weight vest among the equipment (ADR 0034, D7)

A vest keeps its weight and, if adjustable, how far it goes. At a place
that has one, a set of bodyweight work offers it beside the weight, a
tap writing its weight in.

Whats-New: Add a weight vest to your equipment, and put its weight on a bodyweight set with a tap.
Whats-New-De: Trage eine Gewichtsweste bei deiner Ausrüstung ein und übernimm ihr Gewicht mit einem Tipp in einen Satz mit Körpergewicht.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

apps/train/halkyon_train_flutter/test/feature/equipment/place_payload_test.dart

@@ -97,4 +97,33 @@ void main() {
     expect(decodePlace(_bytes([1, 2])), isNull);
     expect(decodePlace(ByteData(0)), isNull);
   });
+
+  test('a weight vest keeps its weight, and how far an adjustable one goes '
+      '(ADR 0034, D7)', () {
+    const place = PlaceContent(
+      name: 'Home',
+      items: [
+        EquipmentItem(
+          kind: EquipmentKind.weightVest,
+          grams: 6000,
+          gramsUpTo: 10000,
+        ),
+        EquipmentItem(kind: EquipmentKind.weightVest, grams: 8000),
+      ],
+    );
+    expect(decodePlace(encodePlace(place)), place);
+  });
+
+  test("an upper weight that isn't above the vest's weight is left out", () {
+    final place = decodePlace(
+      _bytes({
+        'schemaVersion': 1,
+        'name': 'Home',
+        'items': [
+          {'kind': 'weightVest', 'count': 1, 'grams': 8000, 'gramsUpTo': 8000},
+        ],
+      }),
+    );
+    expect(place!.items.single.gramsUpTo, isNull);
+  });
 }