feat(debug): -probes quits after measuring, so a ground check takes 14 s not minutes

The ground measurement was the slowest part of every iteration: the game ran until the shell's
timeout because nothing told it to stop. -probes now logs the top surface, the capsule and the
body's lowest point three seconds after spawn and quits on the next tick. A run went from minutes
to 13.7 s, which is the difference between one experiment per turn and one per five minutes.

Also applied set_complex_collision_as_simple to sidewalks and kerbs, as the terrain already had:
it did not make them block, so that flag is not their problem either.

And a correction that matters: the road is 366 and the sidewalk 380 in the shipped map. The 158 cm
I measured earlier came from the site blend's own Z datum, which sits about 2.2 m below the map's
because the terrain was added after that blend was written. So the float is about 14 cm - the
character stands on the road because the sidewalk does not collide - not the metre it looks like
against the kerb.

MEMORY.md

@@ -526,3 +526,10 @@ Scope: facts and traps that cost time to establish. Planned work lives in [TODO.
 - **So the slab's 279 m aspect ratio was not the cause** of the missing collision — a 20 m slice of the same mesh fails identically. The mesh itself imports with collision that does not block, regardless of size.
 - **What does collide:** `Road_Hollywood` (366) and the engine cube stopgap. What does not: every `Sidewalk_*` and `Kerb_*` slice.
 - **Next place to look:** the sidewalk mesh's geometry - an open surface with no volume, inverted winding, or zero-thickness triangles - rather than the import flags or the size.
+
+## 2026-11-09 — Fast probe loop, and the real heights
+
+- **`-probes` runs the ground measurements and quits**: a measurement run went from minutes to **13.7 s**. Without the switch the game keeps running for the capture pipeline.
+- **The sidewalks' normals are correct** (2790 faces, all pointing up) and they have no loose edges, so winding was not the reason they fail to block.
+- **`set_complex_collision_as_simple` on sidewalks and kerbs did not make them block** either - the terrain needs it, they do not respond to it.
+- **The heights at the player, corrected once more:** the road is **366** and the sidewalk **380** in the shipped map; the 158 cm figure came from the site blend's own Z datum, which is ~2.2 m below the map's because the terrain was added after that blend was written. The float is therefore about **14 cm** - the character stands on the road because the sidewalk does not collide - not the metre it looks like against the kerb.