- NLE track growth is now a display concern: video/subtitle track
lists render reversed (a new track lands on top), audio lists render
in order (a new track lands at the bottom); the graph list always
appends. Track-add undo removes THIS track by id instead of blindly
removing the last one
- add_track returns the actual index of the new track (diffed against
the pre-command list) instead of assuming append-at-end
- status bar proxy segment reflects the real Use Proxy Media switch
instead of a static "Proxy: Off"
- proxy transcode PROGRESS events no longer invalidate the rendered
frame cache on every tick (only completion does) — progress updates
used to keep the playback cache permanently cold while generating
- effect library: live search box (name/type-id substring), Built-in
group header, and the addable-effects table is sorted alphabetically
(built-ins first, then OFX sub-category groups)