Add socket.io/php-socket dependency to support WebSocket functionality
in the development container. Also update package-lock.json to reflect
peer dependency configurations for Socket.IO packages.
Increases client_body_buffer_size from default (8k-16k) to 256k to handle
Sentinel monitoring data in memory instead of buffering to disk. This eliminates
the "client request body is buffered to a temporary file" warning and improves
performance for servers with many containers (50-100+) sending health check data.
Affects both production and development nginx configurations.
