New TS probe driven off railway-envs SSOT. Accepts --env staging|prod and
optional --services CSV; iterates SERVICES where probe[env]===true and
dispatches to per-driver feature-level verifiers. Refuses to start when a
probe-required service is missing a domain for the requested env (no
silent skip). HTTP 200 is necessary but not sufficient.
Adds verify-deploy.drivers.ts dispatch with exhaustive never check on
ProbeDriver, plus one stub module per ProbeDriver literal (shell, docs,
dashboard, dojo, harness, eval, aimock, pocketbase, webhooks, agent).
Stubs fail loud with an explicit "not yet implemented" error so any
accidental real-network invocation surfaces; per-driver feature-level
impls land as subsequent micro-tasks. Refs spec section 3 / section 3.5.
[BLITZ:A5]