feat: add equality operators, make history screen paginated, random performance updates

lib/views/widgets/product_tile.dart

@@ -7,6 +7,7 @@ class ProductTile extends StatelessWidget {
   final Product product;
   final bool enabled;
   final VoidCallback onTap;
+  static const _tileImageSize = 280.0;
 
   const ProductTile({
     required this.product,
@@ -14,16 +15,6 @@ class ProductTile extends StatelessWidget {
     required this.onTap,
   });
 
-  bool get _hasImage {
-    final imagePath = product.imagePath;
-
-    if (imagePath == null || imagePath.isEmpty) {
-      return false;
-    }
-
-    return File(imagePath).existsSync();
-  }
-
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
@@ -32,7 +23,10 @@ class ProductTile extends StatelessWidget {
     final outOfStock = product.stockQuantity <= 0;
     final lowStock =
         product.stockQuantity > 0 &&
-        product.stockQuantity <= product.lowStockThreshold; // adjust name
+        product.stockQuantity <= product.lowStockThreshold;
+
+    final hasImage = product.imagePath != null &&
+        product.imagePath!.isNotEmpty;
 
     final borderColor = outOfStock
         ? scheme.error.withValues(alpha: 0.7)
@@ -59,21 +53,18 @@ class ProductTile extends StatelessWidget {
               children: [
                 Opacity(
                   opacity: outOfStock ? 0.35 : (enabled ? 1 : 0.4),
-                  child: _hasImage
+                  child: hasImage
                       ? Image.file(
                           File(product.imagePath!),
                           fit: BoxFit.scaleDown,
+                          cacheWidth: _tileImageSize.toInt(),
+                          errorBuilder:
+                              (context, error, stackTrace) => _noImage(scheme),
                         )
-                      : Center(
-                          child: Icon(
-                            Icons.image_not_supported_outlined,
-                            size: 34,
-                            color: scheme.onSurface.withValues(alpha: 0.3),
-                          ),
-                        ),
+                      : _noImage(scheme),
                 ),
 
-                if (_hasImage)
+                if (hasImage)
                   Positioned.fill(
                     child: DecoratedBox(
                       decoration: BoxDecoration(
@@ -126,6 +117,16 @@ class ProductTile extends StatelessWidget {
       ),
     );
   }
+
+  Widget _noImage(ColorScheme scheme) {
+    return Center(
+      child: Icon(
+        Icons.image_not_supported_outlined,
+        size: 34,
+        color: scheme.onSurface.withValues(alpha: 0.3),
+      ),
+    );
+  }
 }
 
 class _StockBadge extends StatelessWidget {
@@ -141,8 +142,7 @@ class _StockBadge extends StatelessWidget {
       return const SizedBox.shrink();
     }
 
-    final low =
-        product.stockQuantity <= product.lowStockThreshold; // adjust name
+    final low = product.stockQuantity <= product.lowStockThreshold;
 
     return Container(
       padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),