Fix CORS issue when fetching cover art for downloads

js/downloads.js

@@ -13,16 +13,41 @@ async function getCoverBlob(api, coverId) {
     if (!coverId) return null;
     if (coverCache.has(coverId)) return coverCache.get(coverId);
 
+    const fetchWithProxy = async (url) => {
+        try {
+            const proxyUrl = `https://corsproxy.io/?${encodeURIComponent(url)}`;
+            const response = await fetch(proxyUrl);
+            if (response.ok) return await response.blob();
+        } catch (e) {
+            console.warn('Proxy fetch failed:', e);
+        }
+        return null;
+    };
+
     try {
         const url = api.getCoverUrl(coverId, '1280');
+        // Try direct fetch first
         const response = await fetch(url);
         if (response.ok) {
             const blob = await response.blob();
             coverCache.set(coverId, blob);
             return blob;
+        } else {
+            // If direct fetch fails (e.g. 404 from SW due to CORS), try proxy
+            const blob = await fetchWithProxy(url);
+            if (blob) {
+                coverCache.set(coverId, blob);
+                return blob;
+            }
+        }
+    } catch (e) {
+        // Network error (CORS rejection not handled by SW), try proxy
+        const url = api.getCoverUrl(coverId, '1280');
+        const blob = await fetchWithProxy(url);
+        if (blob) {
+            coverCache.set(coverId, blob);
+            return blob;
         }
-    } catch (error) {
-        console.warn('Cover fetch failed:', error);
     }
     return null;
 }

sw.js

@@ -45,6 +45,9 @@ self.addEventListener('fetch', event => {
                             cache.put(event.request, networkResponse.clone());
                         }
                         return networkResponse;
+                    }).catch(() => {
+                        // If fetch fails (e.g. CORS), return null/error so client handles it
+                        return new Response(null, { status: 404, statusText: 'Image fetch failed' });
                     });
                 });
             })