Add cdp-latency-check.sh and box cdp-latency action

Proper script replacing the inline-SSH latency monitor. Probes each relay /json/version via pinned ports from netvm-names.sh, outputs name:latency_ms:code per node. box-ctl.py cdp-latency runs it and returns JSON.

bin/cdp-latency-check.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+# cdp-latency-check.sh — measure CDP relay latency per node.
+#
+# Probes each node's host-side relay (PEER_IP:CDP_PORT from netvm-names.sh,
+# which pins the registry ports) at /json/version and prints one line per
+# node:
+#   name:latency_ms:code
+# On failure (timeout / connection refused / non-200-ish transport error):
+#   name:FAIL:000
+#
+# Self-contained: only needs netvm-names.sh in the same directory and curl.
+set -u
+
+BIN_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck disable=SC1091
+source "$BIN_DIR/netvm-names.sh"
+
+TIMEOUT_S=10
+
+for node in muse pip 646 opm; do
+  netvm_names "$node"
+  url="http://${PEER_IP}:${CDP_PORT}/json/version"
+  probe=$(curl -s -m "$TIMEOUT_S" -o /dev/null -w "%{time_total} %{http_code}" "$url" 2>/dev/null)
+  rc=$?
+  secs=$(printf '%s' "$probe" | awk '{print $1}')
+  code=$(printf '%s' "$probe" | awk '{print $2}')
+  if [ "$rc" -ne 0 ] || [ -z "$code" ] || [ "$code" = "000" ]; then
+    echo "${node}:FAIL:000"
+    continue
+  fi
+  ms=$(awk -v s="$secs" 'BEGIN { printf "%d", (s + 0) * 1000 }')
+  echo "${node}:${ms}:${code}"
+done