Dragging the in or out edge of a selected layer's bar now trims every
selected layer by the same delta from its own in/out point, as in After
Effects. layer.timing gains relative inDelta/outDelta params (seconds,
frame-snapped), clamped to the comp start/end and to one frame of layer;
the drag stays one undo step via the merge key.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
