Discriminator naming which gate failed during canTraverse. Backcompat
additive — pre-locomotion callers reading only reason continue to
work. New consumers (locomotion controllers, programmatic callers)
branch on gate to compose verb-templated rejection prose.
Discriminator naming which gate failed during
canTraverse. Backcompat additive — pre-locomotion callers reading onlyreasoncontinue to work. New consumers (locomotion controllers, programmatic callers) branch ongateto compose verb-templated rejection prose.