feat(inventory): seed/plant clarity + full-screen photo viewer

- Each lot shows a Seeds/Plantel chip (green vs teal, with icon) so mixed
  seed-and-plant varieties read clearly at a glance.
- Germination is hidden on plant lots (it only applies to seeds).
- Tapping a photo in the detail carousel opens a full-screen, swipeable,
  pinch-to-zoom viewer.

Tests: plant lot shows the Plants chip and hides germination. 53 green; Linux runs.

apps/app_seeds/test/ui/variety_detail_screen_test.dart

@@ -3,6 +3,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:tane/data/species_repository.dart';
 import 'package:tane/db/database.dart';
+import 'package:tane/db/enums.dart';
 
 import '../support/test_support.dart';
 
@@ -358,4 +359,32 @@ void main() {
     expect(find.text('Wiki'), findsNothing);
     await disposeTree(tester);
   });
+
+  testWidgets('plant lots show the Plants chip and hide germination', (
+    tester,
+  ) async {
+    final repo = newTestRepository(db);
+    final id = await repo.addQuickVariety(label: 'Tomato');
+    await repo.addLot(
+      varietyId: id,
+      type: LotType.plant,
+      harvestYear: 2024,
+      quantity: const Quantity(kind: QuantityKind.plant, count: 3),
+    );
+
+    await tester.pumpWidget(
+      wrapDetail(
+        repository: repo,
+        varietyId: id,
+        species: newTestSpeciesRepository(db),
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    expect(find.text('Plants'), findsOneWidget); // lot-type chip
+    expect(find.text('Year 2024 · 3 plants'), findsOneWidget);
+    // Germination is seed-only.
+    expect(find.byIcon(Icons.grass_outlined), findsNothing);
+    await disposeTree(tester);
+  });
 }