Fix PDF download links — route through Next.js /api/uploads proxy

frontend/src/app/minutes/page.tsx

@@ -83,8 +83,6 @@ export default async function MinutesPage() {
       return da > db ? -1 : 1;
     });
   const memberCount = docs.filter((d) => !d.isPublic).length;
-  const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL ?? '';
-
   return (
     <div className="bg-color-bg">
       {/* Hero */}
@@ -130,9 +128,9 @@ export default async function MinutesPage() {
                           {formatDate(doc.meetingDate)}
                         </span>
                       )}
-                      {doc.filePath && backendUrl && (
+                      {doc.filePath && (
                         <a
-                          href={`${backendUrl}/${doc.filePath}`}
+                          href={`/api/uploads/${doc.filePath.replace(/^uploads\//, '')}`}
                           target="_blank"
                           rel="noopener noreferrer"
                           className="card-link text-sm font-medium underline whitespace-nowrap"