release 1.13.6: env-only machine paths and SSH hosts

Load ~/.config/taler-monitoring/env (taler-monitoring-env profiles)
before suite defaults. Drop hardcoded operator homes and host aliases
from scripts; apply/staging/www/secrets/wallet via env.

metrics.sh

@@ -513,7 +513,7 @@ metrics_taler_load() {
     _m_bank="${INSIDE_BANK_CTR:-stage-lfp-bank}"
     _m_mer="${INSIDE_MERCHANT_CTR:-stage-lfp-merchant}"
     _m_ex="${INSIDE_EXCHANGE_CTR:-stage-lfp-exchange-ansible}"
-    _m_ssh="${INSIDE_SSH:-francpaysan-stage-user}"
+    _m_ssh="${INSIDE_SSH:-}"
   fi
   remote_py=$(cat <<PY
 import base64, json, os, re, subprocess, time
@@ -866,7 +866,7 @@ metrics_report_load() {
     return 0
   fi
   if ! metrics_taler_load "$out" "$label"; then
-    warn "load ${label}" "probe failed via ${KOOPA_SSH:-?} — try KOOPA_SSH=koopa-external"
+    warn "load ${label}" "probe failed via ${KOOPA_SSH:-?} — set KOOPA_SSH / KOOPA_SSH_FALLBACKS in env"
     return 1
   fi
   while IFS= read -r line; do