Disabled thinking option now sent to API

Patch Changes

• 0aa0ff3: fix(anthropic): forward thinking: { type: 'disabled' } to the API instead of stripping it

  Previously, setting providerOptions.anthropic.thinking = { type: 'disabled' } (or top-level reasoning: 'none') was accepted by the schema but silently dropped from the outgoing request. For models that default thinking on (e.g. Sonnet 5), this left thinking enabled and could consume a small max_tokens budget entirely. The disabled value is now sent to the Anthropic Messages API.