Allow users to set custom disk usage thresholds per mounted filesystem
on host agents, rather than applying a single threshold to all volumes.
This addresses NAS/NVR use cases where some volumes (e.g., NVR storage)
intentionally run at 99% while others need strict monitoring.
Backend:
- Check for disk-specific overrides before using HostDefaults.Disk
- Override key format: host:<hostId>/disk:<mountpoint>
- Support both custom thresholds and disable per-disk
Frontend:
- Add 'hostDisk' resource type
- Add "Host Disks" collapsible section in Thresholds → Hosts tab
- Group disks by host for easier navigation
Closes#1103
rcourtman
9cd53814a3