DiskUsage and ContainerCrash alerts now fire webhooks via
send_webhook() after pushing WebSocket notifications. Added
data_dir parameter to spawn_metrics_collector for webhook config
access.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Implements monitoring/collector.rs that collects per-container CPU/RAM/network/disk,
system-wide metrics, RPC latency, and WebSocket connection count every 60 seconds.
Data stored in dual ring buffers: 1-min resolution (24h) and 15-min resolution (7d).
Three new RPC endpoints: monitoring.current, monitoring.history, monitoring.containers.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
