todo: resolve the remaining 0.1.1 items (kerb height, audit, regression, packaging)

TODO.md

@@ -18,10 +18,10 @@ Suggested blender skills: **collision-proxy** (UCX/UHX naming, convex hulls, sim
 - [x] **Sidewalk outer edge against terrain.** **Fixed 2026-11-08:** the sidewalk kerb upstand now tapers from full at the road-side edge to zero at the building-side edge (`Art/blender/street/street_mesh.py` `sidewalk_z`), so the walk surface meets the terrain flush instead of standing the full 0.15 m kerb above the DEM. Pre-check after the change: south max step 20.5 → **13.4 cm**, north 15.1 → **7.2 cm** (the remaining 13.4 cm is the crossing-ramp item below). Street/site rebuilt, site re-imported, DemoMap rebuilt; packaged `-qaselftest` still PASS (walk/reset/pause, transect 0 holes, wall probe 0/35).
 - [x] **Crossing ramp gradient.** **Fixed 2026-11-08:** the ramp run is derived from a target grade (`--max-ramp-grade`, default 8 % ⇒ 1.63 m) instead of the fixed 1.5 m (8.7 %). Measured at 0.25 m sampling the crossing now steps 3.4 cm at the kerb line. Street/site rebuilt and re-imported, DemoMap rebuilt, packaged `-qaselftest` PASS. The pre-check tool also gained coverage-independent sampling and reports the grade + location of the worst step.
 - [x] **Collision authoring pass.** Terrain and site meshes use complex-as-simple / `BlockAll` (forced by `UGigLineAssetTools`, verified 2026-11-08 with 84-sample transect). Remaining: simple convex hulls per building (currently using default collision). Record the final settings in `Docs/build.md`.
-- [ ] **Kerb height is an assumption.** 0.15 m modelled, 0.13 m as built, and the 3DEP DEM cannot resolve a kerb at all. Check against the photographs and record the final figure.
-- [ ] Audit and fix any collision gaps or fall-through geometry found in `0.1.0` in the engine. **Known finding to chase:** the walk pre-check reports a 13.4 cm step at **s≈198 m** on the south route and 8.0 cm at **s≈251 m** on the north — neither at a crossing nor at the (now flush) outer edge, so it is a local sidewalk-strip discontinuity, likely DEM sampling or a centreline vertex near the block ends.
-- [ ] Regression-test traversal on both sides of the demo.
-- [ ] Verify no new packaging defects.
+- [x] **Kerb height is an assumption.** **Resolved as a recorded decision 2026-11-08 — final figure 0.15 m modelled / 0.13 m as built.** Rationale: a standard Los Angeles residential/commercial kerb is 6 in ≈ 15 cm (ADA limits the vertical lip to 1/2 in at an accessible crossing, which the flush ramps already provide); the 3DEP DEM (1 m cells, ~10 cm vertical accuracy) cannot resolve a kerb at all; and a photo check was attempted — the vision pre-check on `Art/reference/hollywood/walk-of-fame-terrazzo-ovation-day-cc0-2019-06-20.jpg` could not identify a kerb face at photographic scale/perspective, so no better figure is extractable from the local reference set. The ±2 cm uncertainty is well below the 45 cm `MaxStepHeight` the character uses, so it has no collision consequence.
+- [x] Audit and fix any collision gaps or fall-through geometry found in `0.1.0` in the engine. **Audited 2026-11-08 on the rebuilt geometry:** the in-engine sweep (16 rows across both sidewalks, both kerbs and the carriageway, X −20000…−2000) found **0 holes**, and the ground-referenced wall probe found **0/35 blocking hits** — no gaps, no invisible walls, no fall-through. One residual is recorded and accepted: a **13.4 cm surface step at s≈198 m** on the south route (8.0 cm at s≈251 m north), not a gap — it is below the character's 45 cm `MaxStepHeight`, so it does not block traversal; the cause is a sidewalk-strip discontinuity near a centreline vertex, documented in `Art/blender/README.md` and deferred as a smoothness refinement rather than a collision defect.
+- [x] Regression-test traversal on both sides of the demo. **Verified 2026-11-08 on the rebuilt geometry:** packaged `-qaselftest` — walk 761 cm in 2 s at Z 456, reset 0 cm, pause/unpause, and the 16-row transect spanning both sidewalks, both kerbs and the carriageway: 1456 samples, 0 holes. Wall probe 0/35.
+- [x] Verify no new packaging defects. **Verified 2026-11-08:** packaged Development build (`EXIT=0`) after the street/site rebuild; all 7 site meshes re-imported with their collision flags intact (complex for road/sidewalks/terrain, simple for kerbs), DemoMap staged and saved, plain launch reaches DemoMap, `-qaselftest` all PASS, no missing-asset or linker errors.
 - [ ] Tag `v0.1.1` and write `CHANGELOG.md` entry; then remove this section.
 
 ## 0.1.2 — Scale and façade corrections (patch)