* feat(studio): preview new tracks at drop boundaries
* fix(studio): preserve group ownership across overlapping moves
* refactor(studio): share timeline drop decisions and fixtures
* fix(studio): open an empty audio zone below visual tracks
* fix(studio): cancel thumbnails when project pages leave
* refactor(studio): share thumbnail regression setup
* test(studio): gate thumbnail socket release in browser CI
* chore(studio): keep optimistic revision comments within ratchet
* fix(studio): pin regression proxy requests to its backend
* test(studio): bound the proxy origin probe
* test(studio): probe proxy origin through the ready document
* docs(studio): map filmstrip clip rendering contract
* feat(studio): give timeline clips a separate filmstrip name band
* test(studio): require the filmstrip picture wrapper
* fix(studio): keep fallback clip warnings clear of menu badges
* fix(studio): reserve clip text space beside status badges
* fix(studio): separate clip FX and fade hit areas
* fix(studio): separate clip tool pointer targets
* fix(studio): reserve FX space without lowering fades
* refactor(studio): trim fade geometry measurement
* test(studio): refresh fade target after closing FX menu
* test(studio): collapse keyframe lanes before pointer witness
* test(studio): register filmstrip control browser gate