When entering an interior (e.g. lab from town), the game saves the
player's current position as a return point. When exiting, if the
exit has no explicit targetX/targetY, the system pops the stored
return point and warps back to that exact position.
This means interior exits just need targetMap — the player always
returns to the specific door they entered from, not a hardcoded
position. Falls back to the destination map's spawn if no return
point is stored.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>