GPT Pricing Update

Due to changes in external circumstances, our GPT model pricing has been updated.
The rates have changed as follows:

• GPT-5.6 Sol: from 0.07× the reference rate (7%) to 0.09× (9%)
• GPT-5.6 Terra: from 0.0875× the reference rate (8.75%) to 0.09× (9%)
• GPT-5.6 Luna: from 0.5× the reference rate (50%) to 0.6× (60%)