`max` became a first-class effort tier in d435385a, but the `auto`
classifier prompt still offers only `low|medium|high|xhigh`. On a model
that exposes the tier, `auto` can therefore never reach it — only the
`ultrathink` keyword can, because it bypasses the classifier entirely.
`providers.autoThinkingMaxEffort` (`xhigh` | `max`, default `xhigh`) lifts
that ceiling. Opting in adds `max` to the classifier vocabulary, gated on
the target model actually supporting the tier, and scopes the tie-break
exception to that prompt variant so the default renders byte-for-byte as
before. A classification above the configured ceiling is clamped before
the model clamp, so a hallucinated `max` cannot cross a ceiling the user
did not opt into. The on-device 3-bucket classifier stays capped at
`xhigh`, and the provisional/fallback level still never provisions `max`.
Also corrects the two `Auto-detect per prompt (low-xhigh)` labels and the
stale `xhigh auto ceiling` comment, which the new setting makes wrong.
Éverton Toffanetto
fbd3ebffc6