Fix SQLite absolute path by using four slashes in DATABASE_URL

server/docker-compose.yml

@@ -13,7 +13,7 @@ services:
     volumes:
       - todoflow_db_volume:/app/data
     environment:
-      - DATABASE_URL=${DATABASE_URL:-sqlite:///app/data/todo.db}
+      - DATABASE_URL=${DATABASE_URL:-sqlite:////app/data/todo.db}
       - API_KEYS_RAW=${API_KEYS_RAW:-widget-token-secure-789,ai-agent-token-secure-101}
       - ENV=${ENV:-production}
     networks: