feat(03-02): setup list page, detail page, and item picker

- Create SetupCard component with name, item count, weight, cost display
- Build setups list page with inline create form and grid layout
- Build setup detail page with category-grouped items and sticky totals bar
- Create ItemPicker component in SlideOutPanel with category-grouped checkboxes
- Add onRemove prop to ItemCard for non-destructive setup item removal
- Setup detail has delete confirmation dialog with collection safety note
- Empty states for both setup list and setup detail pages

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/client/components/ItemCard.tsx

@@ -9,6 +9,7 @@ interface ItemCardProps {
   categoryName: string;
   categoryEmoji: string;
   imageFilename: string | null;
+  onRemove?: () => void;
 }
 
 export function ItemCard({
@@ -19,6 +20,7 @@ export function ItemCard({
   categoryName,
   categoryEmoji,
   imageFilename,
+  onRemove,
 }: ItemCardProps) {
   const openEditPanel = useUIStore((s) => s.openEditPanel);
 
@@ -26,8 +28,30 @@ export function ItemCard({
     <button
       type="button"
       onClick={() => openEditPanel(id)}
-      className="w-full text-left bg-white rounded-xl border border-gray-100 hover:border-gray-200 hover:shadow-sm transition-all overflow-hidden"
+      className="relative w-full text-left bg-white rounded-xl border border-gray-100 hover:border-gray-200 hover:shadow-sm transition-all overflow-hidden group"
     >
+      {onRemove && (
+        <span
+          role="button"
+          tabIndex={0}
+          onClick={(e) => {
+            e.stopPropagation();
+            onRemove();
+          }}
+          onKeyDown={(e) => {
+            if (e.key === "Enter" || e.key === " ") {
+              e.stopPropagation();
+              onRemove();
+            }
+          }}
+          className="absolute top-2 right-2 z-10 w-6 h-6 flex items-center justify-center rounded-full bg-gray-100/80 text-gray-400 hover:bg-red-100 hover:text-red-500 opacity-0 group-hover:opacity-100 transition-all cursor-pointer"
+          title="Remove from setup"
+        >
+          <svg className="w-3.5 h-3.5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M6 18L18 6M6 6l12 12" />
+          </svg>
+        </span>
+      )}
       {imageFilename && (
         <div className="aspect-[4/3] bg-gray-50">
           <img