chore(node): preserve pre-canonicalization experiment snapshot

Historical working copy retained for audit before consolidation into main. The canonicalized plugin architecture and later fixes already live in main; this snapshot is not a release or a request to restore obsolete source layout.

apps/node-agent/packaging/prerm

@@ -7,6 +7,12 @@ if [ -d /run/systemd/system ]; then
       exit 1
     fi
   fi
+  if [ -S /run/mission-core-k1/driver.sock ]; then
+    if ! /usr/bin/python3 -I -c 'import http.client,json,socket; c=http.client.HTTPConnection("k1",timeout=5); c.sock=socket.socket(socket.AF_UNIX); c.sock.settimeout(5); c.sock.connect("/run/mission-core-k1/driver.sock"); c.request("GET","/prepare-safe"); r=c.getresponse(); assert r.status==200 and json.load(r).get("safe") is True'; then
+      echo "Mission Core Node: завершите подключение или запись K1 перед обновлением." >&2
+      exit 1
+    fi
+  fi
   mc_node_device_job=$(systemctl show --property=ActiveState --value mission-core-node-realsense-prepare.service 2>/dev/null || true)
   case "$mc_node_device_job" in
     active|activating) echo "Mission Core Node: дождитесь завершения подготовки устройства." >&2; exit 1 ;;
@@ -40,6 +46,8 @@ case "$1" in
         /usr/sbin/sshd -t
         systemctl try-reload-or-restart ssh.service
       fi
+      systemctl stop mission-core-k1.service
+      systemctl disable mission-core-k1.service || true
       systemctl stop mission-core-realsense.service
       systemctl disable mission-core-realsense.service || true
       systemctl stop mission-core-node.service