Fix Telegram avatar proxy headers

src/auth/telegram-bot-login.ts

@@ -105,7 +105,9 @@ export async function fetchTelegramPhoto(fileId: string) {
   }
 
   return {
-    contentType: response.headers.get('content-type') ?? 'image/jpeg',
+    contentType: file.file_path.toLowerCase().endsWith('.png')
+      ? 'image/png'
+      : 'image/jpeg',
     bytes: Buffer.from(await response.arrayBuffer()),
   };
 }