Root cause of stale intro payments: koopa max-ladder minted but accept-uri
failed with taler-wallet-cli not found (SKIP_ACCEPT ×16). Fail early without
CLI/helper; after bank transfer_done keep polling + run-pending for available
coins; pay wait 180s; host-agent max-ladder sets WALLET_CLI PATH.
Per-stack en|fr lives in domains.conf; load_domain_profile sets
TALER_DOMAIN_LANG. FP profiles use lang=fr; workstation LANG=en no longer
overrides. HTML chrome resolves lang from the same conf.