System: position

Position snapshot system.

Maintains prev_position as an immutable snapshot of all entity positions at the start (or end) of a step. Other systems (e.g. portal teleportation, trail generation, damage-on-crossing) rely on this historical information to detect transitions or movement paths.

position_system(state, ctx)

Snapshot current entity positions.

Parameters:

Name	Type	Description	Default
state	State	Current immutable simulation state.	required
ctx	StepContext	Current step context.	required

Returns:

Name	Type	Description
StepContext	StepContext	Updated step context with snapshot of current positions.