Find NAS useradd outside PATH

Prompts used since the previous commit:
- De nas heeft wel een useradd commando. Als ik inlog, kan ik useradd uitvoeren

Special observations:
- Non-interactive SSH sessions may omit /usr/sbin from PATH, so deployment now searches common sbin paths for useradd and nologin.
- verplaats_log.json remains modified from the user's run and was intentionally not staged.

deploy_vps.sh

@@ -45,9 +45,30 @@ set -euo pipefail
 
 sudo -v
 
+find_command() {
+  local name="$1"
+  shift
+  if command -v "$name" >/dev/null 2>&1; then
+    command -v "$name"
+    return 0
+  fi
+  for candidate in "$@"; do
+    if [ -x "$candidate" ]; then
+      printf '%s\n' "$candidate"
+      return 0
+    fi
+  done
+  return 1
+}
+
 if ! id "$APP_USER" >/dev/null 2>&1; then
-  if command -v useradd >/dev/null 2>&1; then
-    sudo useradd --system --home "$APP_DIR" --shell /usr/sbin/nologin "$APP_USER"
+  if USERADD="$(find_command useradd /usr/sbin/useradd /sbin/useradd)"; then
+    NOLOGIN="$(find_command nologin /usr/sbin/nologin /sbin/nologin || true)"
+    if [ -n "$NOLOGIN" ]; then
+      sudo "$USERADD" --system --home "$APP_DIR" --shell "$NOLOGIN" "$APP_USER"
+    else
+      sudo "$USERADD" --system --home "$APP_DIR" "$APP_USER"
+    fi
   else
     APP_USER="$(id -un)"
     echo "useradd not found on remote host; using existing SSH user '$APP_USER' for the service." >&2