Draft: chore: update prompt for Haiku and Sonnet 4.5

What does this merge request do and why?

Latest improved results for the code explain dataset:

• sonnet 4.5 - https://smith.langchain.com/o/477de7ad-583e-47b6-a1c4-c4a0300e7aca/datasets/2c4bf119-96c0-4aa2-9681-ad64219a92e9/compare?selectedSessions=749462a8-5435-4a17-acb3-ef039d1b5cfd&baseline=undefined

• haiku 4.5 - https://smith.langchain.com/o/477de7ad-583e-47b6-a1c4-c4a0300e7aca/datasets/2c4bf119-96c0-4aa2-9681-ad64219a92e9/compare?selectedSessions=b9e9970e-7989-4df3-a497-72156d21a055&baseline=undefined

Results for the code explain dataset - commit cbc09672

• Sonnet 4.5 - https://smith.langchain.com/o/477de7ad-583e-47b6-a1c4-c4a0300e7aca/datasets/2c4bf119-96c0-4aa2-9681-ad64219a92e9/compare?selectedSessions=edfee1bc-94a0-4ae8-a857-4f5c1d80ce7a&baseline=undefined
• haiku 4.5 - https://smith.langchain.com/o/477de7ad-583e-47b6-a1c4-c4a0300e7aca/datasets/2c4bf119-96c0-4aa2-9681-ad64219a92e9/compare?selectedSessions=1ff3512d-894f-4f82-aa9f-e23d47707df3&baseline=undefined

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

Merge request checklist

• 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.