fix(placement): character and car stand on the ground, not above it

Both floats had different causes and both were measured.

Character: the player start sat at Z 600 while the capsule settles at Z 561 on this
pavement - the QA self-test has been reporting that settle height all along - so the soles
hung 39 cm in the air. The start now uses the measured 561.

Car: the template's lowest geometry is exhaust and underbody, so grounding the model on its
whole bounding box left the tyres 4 cm above the origin. It is grounded on its WHEELS now.
The staged height is 342 rather than the traced road height of 366, because at 367 the
render still showed a gap: the trace and the visible road mesh disagree by about 25 cm at
that spot, and the number is recorded as empirical rather than derived.

Also adds a foot-contact log to the character at BeginPlay (actor Z, ground, capsule half,
mesh bottom, gap) so the next float is a measurement rather than a look.

TODO.md

@@ -23,6 +23,7 @@ Actionable task list for this project. This file is the single, central place fo
   - **Also open:** LOD group wiring, enter/exit, driving route, handling.
 - [x] 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 2026-11-09** — the car renders, built from the owner's `hot hatch.blend`. **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.
+- [x] Fix the character and car floating. Character: the player start at Z 600 left the soles 39 cm in the air (the capsule settles at 561 on this pavement); the start is now the measured 561. Car: the template's lowest geometry is exhaust, so grounding on the whole model put the tyres 4 cm above the origin - it is now grounded on its wheels, staged at Z 342 after the traced road height (366) disagreed with the visible road by ~25 cm.
 - [ ] Implement enter/exit interaction.
 - [ ] Build a closed driving route with boundaries.
 - [ ] Tune basic handling to a drivable state.