feat(k8s,proxmox): add etcd tuning for spinning-disk storage + VM disk audit script

k8s/install-cp.sh: add --etcd-arg heartbeat-interval=1000 and
election-timeout=5000 to both bootstrap and join commands. Gives etcd 5x
margin to absorb transient fsync stalls on spinning-disk-backed NFS
storage (default 500ms/1500ms too tight for this environment).

proxmox/perf/scripts/audit-vm-disks.sh: new script to audit disk cache
configuration on all VMs across Proxmox hosts. Identifies VMs that would
benefit from cache=writeback (especially etcd/database workloads on
NFS-backed spinning disk).

[#392] [#393]

💘 Generated with Crush

Assisted-by: Crush:glm-5.2

proxmox/perf/scripts/audit-vm-disks.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/bash
+# Audit all VM disk configs on a Proxmox host
+set -uo pipefail
+HOST="$1"
+PROX_HOST="$HOST" bash tests/remote.sh prox '
+  qm list 2>/dev/null | tail -n +2 | while read -r line; do
+    vmid=$(echo "$line" | awk "{print \$1}")
+    name=$(echo "$line" | awk "{print \$2}")
+    status=$(echo "$line" | awk "{print \$3}")
+    echo "VMID=$vmid NAME=$name STATUS=$status"
+    qm config "$vmid" 2>/dev/null | grep -E "^(scsi|virtio|ide)[0-9]+:" | sed "s/^/  /"
+    echo ""
+  done
+'