fix(hero): export smoothing groups; give the facade real collision

UE export hygiene (unreal-export skill checklist) plus a gameplay defect the new
probe caught:

- FBX export now uses mesh_smooth_type="FACE" (was OFF, which is why every import
  logged "No smoothing group information was found"), and the round parts are
  shaded with shade_smooth_by_angle(35 deg) before export, so columns and
  medallions read round instead of faceted.
- SM_HeroFacade had complex-only collision, so capsule sweeps and line traces
  passed through the wall: the player could walk through the hero facade.
  auto_generate_collision was tried and rejected (coarse hulls bulged into the
  street; the QA wall probe went 0/35 -> 2/35). It now uses UseComplexAsSimple,
  saved on the asset, like the terrain.
- New -qaselftest facade occlusion probe: 40 m traces sideways from the road
  centre at walking height, required only where a building is staged (explicit X
  spans mirroring ue_build_demo_map). Result 0/9 -> PASS, alongside transect
  0 holes and wall probe 0/35.

Docs: release-checks records the probe and both collision attempts; Tools/README
lists the new phase; MEMORY records the smoothing/collision lessons.

Tools/README.md

@@ -57,7 +57,7 @@ Geographic tools live in [`Geo/tools/`](../Geo/README.md) and the Blender-side b
 | Command | Purpose |
 | --- | --- |
 | `UnrealEditor <uproject> /Game/Hollywood/DemoMap -game -qaselftest` | Headless behaviour check: drives forward input for 2 s, then resets and pauses. Logs `GigLine QA: ... PASS/FAIL` lines and a final `RESULT`. Runs only with `-qaselftest`, so normal play is unaffected. |
-| `-qaselftest` phases | Walk, reset, pause/unpause, a 16-row seam transect (0 holes) and a ground-referenced wall probe (0/35), plus a frame-time capture writing `Saved/Profiling/perf-walk-frametimes.csv` and logging `GigLine PERF:`. |
+| `-qaselftest` phases | Walk, reset, pause/unpause, a 16-row seam transect (0 holes), a ground-referenced wall probe (0/35) and a **facade occlusion probe** that fires sideways from the road centre and requires a blocking wall wherever a building is staged (0/9), plus a frame-time capture writing `Saved/Profiling/perf-walk-frametimes.csv` and logging `GigLine PERF:`. |
 | `gigline.SetupLogs` cvar | Spawn/input setup logging, **off by default** (`DefaultEngine.ini [ConsoleVariables]`); enable at runtime with `gigline.SetupLogs 1`. |
 
 ## Reference and concept generation