fix(inventory): tappable photo dots + non-truncated quantity scale

- Photo carousel dots are now tappable (jump to that photo) with a larger hit
  area, so you can browse all images even when swiping the small thumbnail is
  awkward.
- The quantity unit scale is a Wrap instead of a horizontal scroll, so every
  unit stays visible instead of being cut off.

apps/app_seeds/lib/ui/variety_detail_screen.dart

@@ -927,7 +927,16 @@ class _PhotoGalleryState extends State<_PhotoGallery> {
             ),
           ),
           const SizedBox(height: 6),
-          if (photos.length > 1) _Dots(count: photos.length, active: page),
+          if (photos.length > 1)
+            _Dots(
+              count: photos.length,
+              active: page,
+              onTap: (i) => _controller.animateToPage(
+                i,
+                duration: const Duration(milliseconds: 250),
+                curve: Curves.easeInOut,
+              ),
+            ),
           TextButton.icon(
             key: const Key('photo.add'),
             onPressed: () => _addPhoto(cubit),
@@ -968,10 +977,11 @@ class _CircleIconButton extends StatelessWidget {
 }
 
 class _Dots extends StatelessWidget {
-  const _Dots({required this.count, required this.active});
+  const _Dots({required this.count, required this.active, this.onTap});
 
   final int count;
   final int active;
+  final ValueChanged<int>? onTap;
 
   @override
   Widget build(BuildContext context) {
@@ -979,13 +989,20 @@ class _Dots extends StatelessWidget {
       mainAxisAlignment: MainAxisAlignment.center,
       children: [
         for (var i = 0; i < count; i++)
-          Container(
-            width: 6,
-            height: 6,
-            margin: const EdgeInsets.symmetric(horizontal: 2),
-            decoration: BoxDecoration(
-              shape: BoxShape.circle,
-              color: i == active ? seedGreen : Colors.black26,
+          GestureDetector(
+            behavior: HitTestBehavior.opaque,
+            onTap: onTap == null ? null : () => onTap!(i),
+            child: Padding(
+              // Bigger, tappable hit area around each dot.
+              padding: const EdgeInsets.all(6),
+              child: Container(
+                width: 8,
+                height: 8,
+                decoration: BoxDecoration(
+                  shape: BoxShape.circle,
+                  color: i == active ? seedGreen : Colors.black26,
+                ),
+              ),
             ),
           ),
       ],