feat: add caching debug logs and configurable max concurrent requests for Komga API to enhance performance monitoring

ENV.md

@@ -17,6 +17,12 @@ NEXTAUTH_URL=https://ton-domaine.com
 # Admin User (optional - default password for julienfroidefond@gmail.com)
 ADMIN_DEFAULT_PASSWORD=Admin@2025
 
+# Cache Debug (optional - logs cache operations)
+# CACHE_DEBUG=true
+
+# Komga Request Queue (optional - max concurrent requests to Komga, default: 2)
+# KOMGA_MAX_CONCURRENT_REQUESTS=5
+
 # Node Environment
 NODE_ENV=production
 ```