* fix(models): validate Claude extended thinking budgets
* fix(models): preserve Claude thinking budget semantics
* fix(models): isolate Claude auto thinking budgets
* fix(models): preserve interleaved Claude thinking budgets
Consolidate the additional thinking-budget boundary and type coverage from PR #6482 into #6060. Keep copied automatic budgets and preserve valid manual interleaved budgets with supported models, tools, and the effective beta header. Document the validation scope and cover native payload construction and SDK header precedence.
* docs(models): avoid upstream Claude setup overlap
---------
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
