feat: Replace direct UNESCO image URL with backend proxy URL in HeritageCard

[zigzagdev]

Parent issue

#475

Overview

Update the HeritageCard React component to point <img src> at the backend proxy endpoint instead of the raw UNESCO URL.

Implementation

// Build proxy URL from the record's primary key
const backendApiUrl = `${process.env.NEXT_PUBLIC_API_BASE_URL}/api/heritage-image/${item.id}`;

// In JSX, replace the existing <img> with:
{item.id && !isImgError ? (
  <img
    src={backendApiUrl}
    alt={title}
    className="h-full w-full object-cover transition-transform duration-300 group-hover:scale-105"
    crossOrigin="anonymous"
    onError={() => setIsImgError(true)}
  />
) : (
  // existing placeholder SVG
)}

Acceptance criteria

• <img src> points to /api/heritage-image/{id} (via env var base URL)
• crossOrigin="anonymous" is set
• onError still triggers the placeholder fallback