Add missing entries and cross-package duplications:
- after_provider_response extension hook (#3128)
- Compact startup header with Ctrl+O toggle (#3267)
- preset example: restore original state on (none) (#3272)
- OSC 8 hyperlinks in markdown (#3248)
- Hyperlink capability detection tightening (#3248)
- OpenAI Responses session_id headers for proxies (#3264)
Add New Features summary at the top of [Unreleased].
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