9ef6136865
There were lot of places, where timeline frame was incorrectly mapped to frame index. For deleting transitions, internal function `seq_retiming_add_key` was added. It can work in frame index domain directly. This is to avoid adding more complexity, since key positions are stored and re-created later. Going through index to frame and back to index would introduce float precision errors. Pull Request: https://projects.blender.org/blender/blender/pulls/129305