[breaking] OpenAI deprecates gpt-5.2-chat-latest and gpt-5.3-chat-latest

The gpt-5.2 and gpt-5.3 chat-latest snapshots were deprecated May 8, 2026 and shut down August 10, 2026. Recommended replacement: gpt-5.5. Effective: 2026-08-10. Migration target: openai/gpt-5.5. Affected: openai/gpt-5.2-chat-latest, openai/gpt-5.3-chat-latest. Severity: breaking. Verification: verified.