[breaking] OpenAI retires GPT-3.5/GPT-4-era models, o1/o3-mini/o4-mini, and gpt-image-1, shutdown October 2026

The second wave of the April 22, 2026 deprecation shuts down October 23, 2026: the remaining gpt-3.5-turbo and gpt-4/gpt-4-turbo aliases, gpt-4.1-nano, gpt-4o-2024-05-13, gpt-image-1, o1, o1-pro, o3-mini, and o4-mini — plus fine-tuned versions (ft-gpt-3.5-turbo, ft-gpt-4, ft-gpt-4.1-nano, ft-babbage-002, ft-davinci-002). Substitutes are gpt-5.5, gpt-5.4-mini/nano, gpt-5.5-pro, and gpt-image-2 per model. Effective: 2026-10-23. Affected: openai/gpt-3.5-turbo, openai/gpt-3.5-turbo-0125, openai/gpt-4, openai/gpt-4-0613, openai/gpt-4-1106-preview, openai/gpt-4-turbo, openai/gpt-4-turbo-2024-04-09, openai/gpt-4.1-nano, openai/gpt-4.1-nano-2025-04-14, openai/gpt-4o-2024-05-13, openai/gpt-image-1, openai/o1, openai/o1-2024-12-17, openai/o1-pro, openai/o1-pro-2025-03-19, openai/o3-mini, openai/o3-mini-2025-01-31, openai/o4-mini, openai/o4-mini-2025-04-16. Severity: breaking. Verification: verified.