Generator effects (bars, checkerboard) can be dragged from the library
onto the timeline, where they land as a standalone five-second clip
built from the node factory; the inspector shows the generator's
parameters as the clip's own chain.
Transitions are no longer junction-only. The render planner accepts a
transition with at least one wired neighbor and blends the missing
side against transparent black, so head transitions fade in from black
and tail transitions fade out to black. add_transition_at_edge creates
those single-sided blocks (wired to just the IN or OUT block), the
default-transition command covers both ends of a lone clip, and an
effect drag dropped near a clip edge routes to the nearest seam or
edge within a one-second window.