fix(synology): use Thumbnail API with size xl for originals to avoid HEIC

Replace SYNO.Foto.Download with SYNO.Foto.Thumbnail (size=xl) for the
original kind, mirroring the Immich approach. Synology's download endpoint
returns the raw file (HEIC for iPhone photos), while the Thumbnail API
always serves a browser-compatible JPEG render.

server/src/services/memories/synologyService.ts

@@ -637,27 +637,20 @@ export async function streamSynologyAsset(
 
     
     //size: 'sm' 240px| 'm' 320px| 'xl' 1280px| 'preview' ?
-    const resolvedSize = size || 'sm';
-    const params = kind === 'thumbnail'
-        ? new URLSearchParams({
-            api: 'SYNO.Foto.Thumbnail',
-            method: 'get',
-            version: '2',
-            mode: 'download',
-            id: parsedId.id,
-            type: 'unit',
-            size: resolvedSize,
-            cache_key: parsedId.cacheKey,
-            _sid: sid.data,
-        })
-        : new URLSearchParams({
-            api: 'SYNO.Foto.Download',
-            method: 'download',
-            version: '2',
-            cache_key: parsedId.cacheKey,
-            unit_id: `[${parsedId.id}]`,
-            _sid: sid.data,
-        });
+    // Use Thumbnail API for both thumbnail and original — avoids serving raw HEIC files
+    // (original uses xl size to get a full-resolution JPEG-compatible render)
+    const resolvedSize = kind === 'original' ? 'xl' : (size || 'sm');
+    const params = new URLSearchParams({
+        api: 'SYNO.Foto.Thumbnail',
+        method: 'get',
+        version: '2',
+        mode: 'download',
+        id: parsedId.id,
+        type: 'unit',
+        size: resolvedSize,
+        cache_key: parsedId.cacheKey,
+        _sid: sid.data,
+    });
     if (passphrase) params.append('passphrase', passphrase);
 
     const url = _buildSynologyEndpoint(synology_credentials.data.synology_url, params.toString());

server/tests/integration/memories-synology.test.ts

@@ -166,16 +166,6 @@ vi.mock('../../src/utils/ssrfGuard', async () => {
       });
     }
 
-    // Original download
-    if (apiName === 'SYNO.Foto.Download') {
-      const imageBytes = Buffer.from('fake-synology-original');
-      return Promise.resolve({
-        ok: true, status: 200,
-        headers: { get: (h: string) => h === 'content-type' ? 'image/jpeg' : null },
-        body: new ReadableStream({ start(c) { c.enqueue(imageBytes); c.close(); } }),
-      });
-    }
-
     return Promise.reject(new Error(`Unexpected safeFetch call to Synology: ${u}, api=${apiName}`));
   }