fix(leaks): what play allocated every frame and never freed - a shadow uniform's name, the Tick, a ridden vehicle's moves

Found with malloc_history over 1200 frames of play without the interface (the first Ludic function
on each allocating stack, live bytes at two marks): sh_loc built `name + "[0]"` per program per pass
per frame - 24.6 MB of 33 in the window; its callers pass both names as literals now. tick_set fills
the frame loop's one Tick instead of tick_new making one a frame. A ridden boat or horse said
VEHICLE_MOVED as a new fact every frame; the metres are added up in VehiclesState and taken once
(vehicle_moved_take / _kind / _x / _z). Play's growth without the interface: 92 -> 14.7 MB a minute
(maroon-lake tests/leakcheck.sh); what is left is phys_push (Physics' fix on lang/nav) and the HUD's
strings. Packages 407, ludic-dev test 305 pass.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/ludic.vehicles/ports.ludic

@@ -43,6 +43,10 @@ export state VehiclesState {
   ve_kept_boat: bool = false
   ve_kept_food: float = 40.0
   ve_ids: int = 0
+  ve_moved: float = 0.0        # metres the ridden vehicle covered since the game last took them
+  ve_moved_kind: int = 0
+  ve_moved_x: float = 0.0
+  ve_moved_z: float = 0.0
   ve_sx: float = 0.0
   ve_sz: float = 0.0
   ve: VehicleTable = ve__new()