Fix shop filter spacing: consistent checkbox gaps, more room below mobile filter bar

CategoryFilter used gap-4 between the category group and the
availability checkbox but gap-2 within the category list itself,
reading as uneven spacing. ProductGrid's <lg filter bar only had
pb-6 before the product grid.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/shop/components/CategoryFilter.tsx

@@ -41,7 +41,7 @@ export function CategoryFilter({ categories }: { categories: string[] }) {
   }
 
   return (
-    <div className="flex flex-col gap-4 w-full">
+    <div className="flex flex-col gap-2 w-full">
       {categories.length > 1 && (
         <div className="flex flex-col gap-2 w-full">
           <p className="font-bold text-body-sm text-text-primary">Kategorie</p>

app/shop/components/ProductGrid.tsx

@@ -80,7 +80,7 @@ export async function ProductGrid({
           as before. lg+: they move into a left sidebar instead (see aside
           below), so this is hidden there to avoid rendering twice. */}
       {hasSidebarFilter && (
-        <div className="lg:hidden flex flex-col gap-4 pb-6">
+        <div className="lg:hidden flex flex-col gap-4 pb-10">
           <PriceRangeFilter catalogMin={catalogMin} catalogMax={catalogMax} />
           <CategoryFilter categories={allCategories} />
         </div>