Changes

PR #1995 by ksylvan: OpenAI gpt-4o, GPT-4 deprecations, plus other model list updates

• Update default summarize model to claude-sonnet-4-5
• Replace gpt-4o and gpt-4o-mini references with gpt-5.2 and gpt-5-mini throughout documentation and code
• Remove deprecated GPT-4 models (gpt-4o, gpt-4o-mini, gpt-4.1, gpt-4.1-mini) from image generation supported list, effective February 13, 2026
• Add MiniMax-M2.5 and M2.5-lightning to static models list
• Update tests to use gpt-5.2 instead of gpt-4o as the example supported model