Add '{push-mailcow-cert.sh}'

Add script that pushes newly renewed ssl certificate to Mailcow VM staging area.  Uses '{deploy-staged-cert.sh}' to push new cert.

push-mailcow-cert.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+#
+# push-mailcow-cert.sh   (runs on Nginx Proxy Manager host)
+# Pushes the npm-5 (mail.wittenberger.us) cert to the mailcow VM when it changes.
+#
+# Requires: an SSH key for a dedicated push user on the mailcow VM (see notes).
+
+set -euo pipefail
+
+# ---- CONFIG ---------------------------------------------------------------
+NPM_CERT_DIR="/etc/nginx/letsencrypt/live/npm-5"   # mail.wittenberger.us cert
+MAILCOW_HOST="<redacted>"                           # ssh host/alias or IP of mailcow VM
+MAILCOW_SSH_USER="certsync"                         # dedicated low-priv user on mailcow VM
+SSH_KEY="/root/.ssh/mailcow_certsync"               # private key for that user
+REMOTE_STAGING="/home/certsync/incoming"            # staging dir on mailcow VM
+# ---------------------------------------------------------------------------
+
+SRC_CERT="${NPM_CERT_DIR}/fullchain.pem"
+SRC_KEY="${NPM_CERT_DIR}/privkey.pem"
+
+log() { echo "[$(date '+%Y-%m-%d %H:%M:%S')] $*"; }
+
+[[ -r "${SRC_CERT}" ]] || { log "ERROR: cert not readable: ${SRC_CERT}"; exit 1; }
+[[ -r "${SRC_KEY}"  ]] || { log "ERROR: key not readable: ${SRC_KEY}"; exit 1; }
+
+# Track last-pushed fingerprint locally so it only pushes on change.
+STATE_FILE="/var/lib/mailcow-cert-push/last_fp"
+mkdir -p "$(dirname "${STATE_FILE}")"
+
+new_fp=$(openssl x509 -noout -fingerprint -sha256 -in "${SRC_CERT}")
+cur_fp=""
+[[ -r "${STATE_FILE}" ]] && cur_fp=$(cat "${STATE_FILE}")
+
+if [[ "${new_fp}" == "${cur_fp}" ]]; then
+  log "Cert unchanged; nothing to push."
+  exit 0
+fi
+
+log "Cert changed — pushing to ${MAILCOW_HOST}."
+
+# rsync both files into the staging dir. Trailing dot files copied with perms.
+rsync -azL --chmod=F600 \
+  -e "ssh -i ${SSH_KEY} -o StrictHostKeyChecking=accept-new" \
+  "${SRC_CERT}" "${SRC_KEY}" \
+  "${MAILCOW_SSH_USER}@${MAILCOW_HOST}:${REMOTE_STAGING}/"
+
+echo "${new_fp}" > "${STATE_FILE}"
+log "Push complete."