Turn an authored camera block into a full CameraSnapshot, starting from
the LIVE pose so every field the author left out keeps its current value.
That is what lets a waypoint name only a target_node to re-aim without
moving, or only a position to move without re-aiming. target_node wins
over target (the scene-level camera block's rule); an unresolvable node
warns and falls back to target, then to the live target.
Turn an authored camera block into a full
CameraSnapshot, starting from the LIVE pose so every field the author left out keeps its current value. That is what lets a waypoint name only atarget_nodeto re-aim without moving, or only apositionto move without re-aiming.target_nodewins overtarget(the scene-level camera block's rule); an unresolvable node warns and falls back totarget, then to the live target.