Align metric names with Prometheus naming conventions

Use base units, export cumulative values as _total counters, update docs, dashboards and rules.

metrics/pve_node_disk_collector.go

@@ -38,13 +38,13 @@ func NewPveNodeDiskCollector(apiClient *proxmox.PveApiClient, registry *TTLRegis
 	// Node disk wearout.
 	c.wearout = NewTTLGaugeVec(
 		prometheus.GaugeOpts{
-			Name: "pve_node_disk_wearout",
-			Help: "Node disk wearout percent.",
+			Name: "pve_node_disk_wearout_percent",
+			Help: "Node disk wearout in percent (0-100).",
 		},
 		[]string{"cluster", "node", "wwn", "type", "model", "serial", "vendor", "used", "osd_id"},
 		5*time.Minute,
 	)
-	c.registry.Register(c.healthy)
+	c.registry.Register(c.wearout)
 
 	// Node disk size in bytes.
 	c.sizeBytes = NewTTLGaugeVec(