perf: skip Next.js image re-optimization and stream proxy responses

Thumbnails are already optimized (WebP) by the API, so disable Next.js
image optimization to avoid redundant CPU work. Switch route handlers
from buffering (arrayBuffer) to streaming (response.body) to reduce
memory usage and latency.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/backoffice/app/api/books/[bookId]/pages/[pageNum]/route.ts

@@ -21,19 +21,16 @@ export async function GET(
     const response = await fetch(apiUrl.toString(), {
       headers: { Authorization: `Bearer ${token}` },
     });
-    
+
     if (!response.ok) {
-      return new NextResponse(`Failed to fetch image: ${response.status}`, { 
-        status: response.status 
+      return new NextResponse(`Failed to fetch image: ${response.status}`, {
+        status: response.status
       });
     }
-    
-    // Récupérer le content-type et les données
+
     const contentType = response.headers.get("content-type") || "image/webp";
-    const imageBuffer = await response.arrayBuffer();
-    
-    // Retourner l'image avec le bon content-type
-    return new NextResponse(imageBuffer, {
+
+    return new NextResponse(response.body, {
       headers: {
         "Content-Type": contentType,
         "Cache-Control": "public, max-age=300",