Replace df-based auto-discovery with UUID-based detection using NixOS
hardware configuration data. Each host now has predefined filesystem
configurations with predictable metric names.
- Add FilesystemConfig struct with UUID, mount point, and filesystem type
- Remove auto_discover and devices fields from DiskConfig
- Add host-specific UUID defaults for cmbox, srv01, srv02, simonbox, steambox
- Remove legacy get_mounted_disks() df-based detection method
- Update DiskCollector to use UUID resolution via /dev/disk/by-uuid/
- Generate predictable metric names: disk_root_*, disk_boot_*, etc.
- Maintain fallback for labbox/wslbox (no UUIDs configured yet)
Provides consistent metric names across reboots and reliable detection
aligned with NixOS deployments without dependency on mount order.
Christoffer Martinsson
e7200fb1b0