GPT-5.5 Instant System Card capability — update API payloads to use system_card

AI Impact Summary

GPT-5.5 introduces an Instant System Card capability that applies system-level prompts or policies on every request in real time. This can standardize behavior across calls and simplify fleet onboarding, but it requires client updates to pass the new system_card parameter or payload structure. Teams should validate that existing workflows align with the new semantics and update monitoring to track any changes in model behavior tied to system-card usage.