Set the trailer's camera motion.

Sets the camera motion: { handheld?, moves?: [{ unit, move, shot?, target?, from?, zoom? }], off? } — handheld sways every held shot; a move names its beat by unit (the beat's beatIndex), its shot by number from the read, move snap (onto target, zoom up to 1.5) or reframe (from from to target), or none to clear the beat; one move per beat; beats not listed keep theirs; off: true turns it all off. Refused (400, one sentence naming the fix): a beat with no cut, a shot number it does not have, a shot whose camera already moves or is handheld, a shot where someone speaks on camera, a shot too short for the move, a face not in the shot's cast. Camera motion gives the held shots an operator, the way a documentary camera moves: a handheld sway on the shots that were rendered still (off, subtle, medium; never on a shot whose camera already moves or was filmed handheld, and never so far that a speaking mouth leaves the frame), and at most one move per chapter or beat, on a held shot where nobody speaks on camera: a snap zoom onto a reaction (up to 1.5×, right after a line) or a slow reframe from one face to another already in the frame. It is free, and laid when the master is assembled, as the first step of the film finish and before any type. The sound and timing are never touched. Allowed in any state: before a master the choice is kept for the first assembly; in review, finishing or complete the master is assembled again with it (reassembling). Requires Idempotency-Key. Scope: story:write.