feat(17-03): update client components to use imageUrl from API responses

- Replace all /uploads/ path construction with imageUrl presigned URLs
- Add imageUrl prop to ItemCard, CandidateCard, CandidateListItem, ComparisonTable
- Update ImageUpload to use presigned URLs + local preview for new uploads
- Pass imageUrl through from parent components (CollectionView, forms, routes)

src/client/components/CandidateCard.tsx

@@ -14,6 +14,7 @@ interface CandidateCardProps {
 	categoryName: string;
 	categoryIcon: string;
 	imageFilename: string | null;
+	imageUrl?: string | null;
 	productUrl?: string | null;
 	threadId: number;
 	isActive: boolean;
@@ -33,6 +34,7 @@ export function CandidateCard({
 	categoryName,
 	categoryIcon,
 	imageFilename,
+	imageUrl,
 	productUrl,
 	threadId,
 	isActive,
@@ -142,9 +144,9 @@ export function CandidateCard({
 				</span>
 			)}
 			<div className="aspect-[4/3] bg-gray-50">
-				{imageFilename ? (
+				{imageUrl ? (
 					<img
-						src={`/uploads/${imageFilename}`}
+						src={imageUrl}
 						alt={name}
 						className="w-full h-full object-cover"
 					/>