feat: add Claude Sonnet 4.5 as selectable model
What does this merge request do and why?
This MR adds Anthropic's new model Sonnet 4.5 to the system's configuration.
Merge request checklist
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Tests added for new functionality. If not, please raise an issue to follow up. -
Documentation added/updated, if needed. -
If this change requires executor implementation: verified that issues/MRs exist for both Go executor and Node executor or confirmed that changes are backward-compatible and don't break existing executor functionality.