Timeline

Key	Does
`Space`	Play / pause
`J` / `K` / `L`	Rewind one second / pause / play
`←` `→`	Previous / next frame (Motion mode); `Shift` jumps 10 frames
`Home` `End`	Go to start / end
`I` `O` or `B` `N`	Work area starts / ends here
`M`	Add a marker
`Shift+J` `Shift+K`	Previous / next keyframe
`[` `]`	Move the clip to start / end here
`⌥[` `⌥]`	Trim the clip start / end to here

Timeline conveniences:

Drag over the timeline to select keyframes, then duplicate with Cmd+D.
Mute an animation lane to compare with and without it.
Cmd+Enter jumps between a layer and its keyframes.
Select several segments and Group them into one that moves as a unit.
Dragging a keyframe shows a snap guide when it locks onto another key, clip edge, marker or the playhead.
Comments pinned at a moment show on the timeline.
Videos run and export at up to 120 fps (rendered on servers). Unverified: the frame-rate list in the editor; see FRAME_RATES in src/lib/motion/design.ts.