Salvaged from #4627 by @perejaslav. Core Hermes already supports
reasoning_effort=max; this closes the WebUI parity gap (Anchor-A) — adds
max to VALID_REASONING_EFFORTS + dropdown/chip/reasoning-command, keeps
the degrade ladder for capped models.
Co-authored-by: perejaslav <perejaslav@users.noreply.github.com>