fix(placement): the player stands on the sidewalk, at last - 32 cm was the whole float

The player start was at Y -1150, and the north sidewalk slice at that X spans Y -1734..-1182. He was
standing 32 cm south of it, on the roadway - which is why every trace named Road_Hollywood and every
sidewalk fix changed nothing. Moved to Y -1450 and the capsule now rests on the sidewalk:

  top surface under player: Z=158 mesh=Sidewalk_North_07 (actor Z 248)
  body: mesh bottom 161, capsule bottom 161

The cameras that frame the pawn moved with him, and the car now sits on the measured carriageway at
366 rather than the 342 it had.

The captures still read as floating in the vision judge's opinion, and the table says why honestly:
the placements measure correct, but at this sun angle the shadows fall well away from the objects,
which is what the judge is reacting to.

All 23 captures are regenerated and await a fresh approval.

Tools/ue_build_demo_map.py

@@ -701,7 +701,7 @@ def build():
     # The invisible sidewalk collision slab is retired: the site export now slices the
     # sidewalks into 20 m pieces, so the walkable surface is real geometry with an honest
     # local height instead of a 279 m slab whose bounding box was the highest point anywhere.
-    spawn(unreal.PlayerStart, unreal.Vector(-13336.0, -1150.0, player_z), "Demo_PlayerStart",
+    spawn(unreal.PlayerStart, unreal.Vector(-13336.0, -1450.0, player_z), "Demo_PlayerStart",
           unreal.Rotator(pitch=0.0, yaw=90.0, roll=0.0))
     log("staged: Demo_PlayerStart on the cut north sidewalk, facing south (+Y)")
 
@@ -718,10 +718,11 @@ def build():
     # Same source: the vehicle's own downward trace in game reports the road under it at
     # Z 366, and the model is grounded in Blender (wheel bottoms at Z 0), so the panels sit
     # at 367 - one centimetre of clearance rather than a visible gap.
-    # 342, not the surface Z the pawn's trace reports (366): with the model grounded on its
-    # wheels the render still showed a ~25 cm gap at that height, so the visible road mesh
-    # and the traced surface disagree here. The number is empirical and says so.
-    vehicle_origin = unreal.Vector(-12950.0, -900.0, 342.0)
+    # The carriageway at this X measures 366 cm in the profile probe, and the model is grounded
+    # on its wheels in Blender, so the panels sit at 366. (The road is ~2 m above the street's
+    # sidewalk in the shipped geometry - a site-data defect recorded in TODO.md - so the car
+    # looks high against the kerb; that is the geometry, not the placement.)
+    vehicle_origin = unreal.Vector(-12950.0, -900.0, 366.0)
     vehicle_rotation = unreal.Rotator(pitch=0.0, yaw=0.0, roll=0.0)
 
     panel_systems = (