The pre-ladder max_tokens rung accepted payment|connection|rate_limit errors on
its retry, so a 429 after a stripped retry reached the credential and
provider-fallback rungs. The ladder's shared `_param_rung_accepts` dropped
rate_limit: a 429 on the retry raised out of the primary call and skipped the
whole fallback chain. Accept it there too, with a rung-level test that the
stripped kwargs and the 429 are handed on rather than raised.
The body claimed `Fixes #109774` while the aux client still sent the generic
`extra_body.reasoning` to Fireworks on every call and only recovered
reactively (an extra 400 round-trip per request). Port @huklaa's profile
override from #109807: Fireworks documents top-level `reasoning_effort`
(`none` disables thinking), and overriding `build_api_kwargs_extras` marks the
profile reasoning-aware so the transport omits the generic fallback on this
route. Extends the salvage with the effort mapping so enabled-with-effort takes
the same wire, with a control that a profile-less route keeps the fallback.
Salvages #109807 (@huklaa).
Co-authored-by: Hukla <129692708+huklaa@users.noreply.github.com>
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