fix(vehicle): spawn on the road, not 2.5 m under it

Measured rather than guessed: a downward trace from the spawn point reports the road
surface at Z 366 cm, while the vehicle was spawned at Z 120. The car was buried; the only
thing visible in the capture was its shadow falling on the road above it. Spawn is now
Z 470, the camera aims at 430, and it settles at Z 470.

Not fixed, and recorded: with the car above ground the capture still shows road and a
shadow with no car. Panels register, report visible=1 with mesh=SM_Vehicle_Body and a
238 cm extent at the expected position, and MarkRenderStateDirty()/UpdateBounds() run
after registration. The shadow proves a collider is there; the visible geometry is not.

Screenshots/README.md now separates the two causes so the next person does not re-fix the
buried spawn.

TODO.md

@@ -21,7 +21,8 @@ Actionable task list for this project. This file is the single, central place fo
   - **Drive test fails, with a specific cause:** `-drivetest` holds full throttle for 3 s and reports speed and distance. Result: `speed=0 cm/s, travelled 2.2 m -> FAIL`, and BeginPlay logs **`0 wheel objects after register`** while the component reports 4 wheel setups. The setups exist but no wheels are created from them, so there is nothing to apply torque to.
   - **Next:** confirm the skeleton's bone names match the setups (`Wheel_FL`, `Wheel_FR`, `Wheel_RL`, `Wheel_RR`) - a name mismatch silently produces zero wheels - and give the front and rear pairs their own `UChaosVehicleWheel` subclasses rather than the base class, which is what the setups point at today.
   - **Also open:** LOD group wiring, enter/exit, driving route, handling.
-- [A] Fix the vehicle not rendering in the scene. **Chased to a strong clue, not yet solved.** The vehicle is staged and runs (`spawned at (-12950,-900,120)`, `9 visual panels attached`, `panel 0 at (-12950,-900,120) visible=1 extent=238`, `settled at Z 119`), and the review capture shows an empty road with only a soft shadow. `Tools/visual_loop.py --verify` passes the frame; `Tools/judge_screenshot.py` returns `verdict=no confidence=1.0`. A downward trace from the vehicle finds **no ground at all** (`ground at Z -9999`), so the car is over a surface without collision or inside geometry - the shadow and the panels are not in the same place. Next: trace the road's collision under the spawn point, then move the staging to a spot with confirmed road collision.
+- [A] Fix the vehicle not rendering in the scene. **Chased to a strong clue, not yet solved.** The vehicle is staged and runs (`spawned at (-12950,-900,120)`, `9 visual panels attached`, `panel 0 at (-12950,-900,120) visible=1 extent=238`, `settled at Z 119`), and the review capture shows an empty road with only a soft shadow. `Tools/visual_loop.py --verify` passes the frame; `Tools/judge_screenshot.py` returns `verdict=no confidence=1.0`. A downward trace from the vehicle finds **no ground at all** (`ground at Z -9999`), so the car is over a surface without collision or inside geometry - the shadow and the panels are not in the same place. **Fixed:** the vehicle was spawned 2.5 m under the road - a downward trace measured the surface at Z 366 cm against a spawn of Z 120, so the body was buried and only its shadow showed. The spawn is now Z 470 and it settles there.
+  - **Still open:** above ground, the capture still shows road plus a shadow and no car. Panels report `visible=1`, `mesh=SM_Vehicle_Body`, extent 238 cm, at the expected position; `MarkRenderStateDirty()` and `UpdateBounds()` run after registration. Next suspects: the pawn's own `SetActorHiddenInGame` path (a vehicle pawn is not a plain actor), or the panels being attached to a root that the physics simulation moves independently of the actor transform.
 - [ ] Implement enter/exit interaction.
 - [ ] Build a closed driving route with boundaries.
 - [ ] Tune basic handling to a drivable state.