fix: invert shopping list icons to black in light mode

White PNG icons were invisible on light backgrounds. Added semantic
--shopping-icon-filter variable (invert(1) in light, none in dark)
applied to card and picker icons.

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "homepage",
-	"version": "1.13.2",
+	"version": "1.13.3",
 	"private": true,
 	"type": "module",
 	"scripts": {

src/app.css

@@ -149,6 +149,9 @@
 	--text-xl: 1.5rem;
 	--text-2xl: 2rem;
 	--text-3xl: 3rem;
+
+	/* Shopping icon filter — white PNGs need invert in light mode */
+	--shopping-icon-filter: invert(1);
 }
 
 /* ============================================
@@ -212,6 +215,8 @@
 		--color-link: var(--nord8);
 		--color-link-visited: #c89fb6;
 		--color-link-hover: var(--nord7);
+
+		--shopping-icon-filter: none;
 	}
 }
 
@@ -261,6 +266,8 @@
 	--color-link: var(--nord8);
 	--color-link-visited: #c89fb6;
 	--color-link-hover: var(--nord7);
+
+	--shopping-icon-filter: none;
 }
 
 /* ============================================

src/routes/[cospendRoot=cospendRoot]/list/+page.svelte

@@ -811,6 +811,7 @@
     max-width: 100%;
     max-height: 100%;
     object-fit: contain;
+    filter: var(--shopping-icon-filter, none);
   }
   .item-card.checked .card-icon {
     filter: grayscale(0.6);
@@ -1016,6 +1017,7 @@
     width: 100%;
     height: 100%;
     object-fit: contain;
+    filter: var(--shopping-icon-filter, none);
   }
 
   .edit-actions {