asset: two north-side background buildings across Hollywood Blvd

- TCL Chinese Theatre (6925) and Madame Tussaud's (6933) exported from the
  verified OSM blockout with ue_metric_v1 (export_north_buildings.py), with a
  Y-mirror so they land north of the road, across from the hero facade.
- ue_import_north_buildings.py imports + stages them in the DemoMap as
  North_TCL_Chinese / North_Madame_Tussauds (TCL Y 1802..9431, Tussaud's
  1888..7586; hero at Y -1450, road centreline ~0).
- render_screenshots.sh now also runs the DemoMap capture pass; added a
  demo-north-buildings camera, so the new buildings get a review shot.
- README/roadmap updated; flat facade materials pending the 0.1.4 patch.

Screenshots/README.md

@@ -117,6 +117,7 @@ Rendered from `/Game/Hollywood/DemoMap`, the walkable level rather than the revi
 | `demo/review-00-demo-spawn-view.png` | The player's own spawn view: north sidewalk, 20 m back, the full 14.5 m of the hero façade across the road |
 | `demo/review-01-demo-street-level.png` | Close street level: portals, flights, banners and the colonnade from the road |
 | `demo/review-02-demo-crossing.png` | From the west end looking along the block |
+| `demo/review-03-demo-north-buildings.png` | **New 2026-11-07:** the two north-side background buildings (TCL Chinese Theatre 6925, Madame Tussaud's 6933) seen from the south sidewalk across Hollywood Blvd — their frontage and mass. From the OSM blockout volumes, mirrored to the north side of the road. |
 
 Known issues in this build, visible in the shots and already on the roadmap: