frontage: south block frontage, plus the placement bug it exposed

Adds the five remaining verified south-side buildings to the demo block
(6922, 6902, 6838 El Capitan Theatre, 6822 Budget, 6806-6820, 6800 Lee Drug)
exported in place from the OSM blockout and staged by the demo builder.

Adding neighbours exposed a pre-existing placement bug that could not be seen
while the hero stood alone:

- UE south is +Y (south sidewalk Y +718..+1447), but the hero facade sat at
  Y -1450 on the NORTH side and at X -12024..-9420, which is 26 m east of the
  6840 footprint (the frontage gap is X -14591..-12082).
- The two north-side buildings were on the SOUTH side, because their exporter
  mirrored Y.

Fixes: hero moved to X -13336 / Y +1307, inside its frontage gap; frontage and
north buildings export without a Y mirror (the FBX preset already lands
Blender -Y south on UE +Y south); player start and demo cameras moved to the
north sidewalk looking south; sun raised to pitch -62 so both frontages read
instead of the north side going to silhouette.

Screenshots re-rendered; the four demo views are marked needs-review because
the whole block changed.

Screenshots/README.md

@@ -23,8 +23,9 @@ and exits — about a minute. The camera list lives in
 
 ## Shot list
 
-All shots ☑ approved 2026-11-07, including the material look pass that changed
-every demo surface.
+Review-map shots ☑ approved. **Demo-map shots: needs review** — the block
+frontage pass (2026-11-07) added the neighbouring buildings and corrected the
+hero and north-building placement, so all four demo views changed.
 
 | # | File | Preview | Map | View | What it shows |
 | --- | --- | --- | --- | --- | --- |
@@ -38,10 +39,10 @@ every demo surface.
 | 8 | `review-hero-portals.png` | [<img src="review-hero-portals.png" alt="hero portals" width="180">](review-hero-portals.png) | Review | 8 m, eye height | Three genuine 1.2 m portal recesses with flights and plinth |
 | 9 | `review-hero-facade-front.png` | [<img src="review-hero-facade-front.png" alt="hero facade front" width="180">](review-hero-facade-front.png) | Review | road side, straight-on | Hero façade elevation and column rhythm |
 | 10 | `review-hero-facade-oblique.png` | [<img src="review-hero-facade-oblique.png" alt="hero facade oblique" width="180">](review-hero-facade-oblique.png) | Review | north-west | Body depth and column line standing proud of the mass |
-| 11 | `demo/review-demo-spawn-view.png` | [<img src="demo/review-demo-spawn-view.png" alt="spawn view" width="180">](demo/review-demo-spawn-view.png) | Demo | spawn point | Spawn view from the north sidewalk: the hero façade across the road under fixed daytime light |
-| 12 | `demo/review-demo-street-level.png` | [<img src="demo/review-demo-street-level.png" alt="street level" width="180">](demo/review-demo-street-level.png) | Demo | eye height, north side | The façade colonnade and columns, sunlit with cast shadows |
-| 13 | `demo/review-demo-crossing.png` | [<img src="demo/review-demo-crossing.png" alt="crossing" width="180">](demo/review-demo-crossing.png) | Demo | along the crosswalk | The designated mid-block crossing at s=130 m (UE X -14956): three continental zebra bars on the asphalt, kerbs flushed to ramps |
-| 14 | `demo/review-demo-north-buildings.png` | [<img src="demo/review-demo-north-buildings.png" alt="north buildings" width="180">](demo/review-demo-north-buildings.png) | Demo | across the Blvd | North-side background buildings (TCL, Tussaud's), lit against the sky |
+| 11 | `demo/review-demo-spawn-view.png` | [<img src="demo/review-demo-spawn-view.png" alt="spawn view" width="180">](demo/review-demo-spawn-view.png) | Demo | north sidewalk | The whole block: hero façade between its neighbours, both sidewalks and the road |
+| 12 | `demo/review-demo-street-level.png` | [<img src="demo/review-demo-street-level.png" alt="street level" width="180">](demo/review-demo-street-level.png) | Demo | eye height, north side | The hero colonnade with the adjacent frontage buildings either side |
+| 13 | `demo/review-demo-crossing.png` | [<img src="demo/review-demo-crossing.png" alt="crossing" width="180">](demo/review-demo-crossing.png) | Demo | along the crosswalk | The designated mid-block crossing at s=130 m (UE X -14956): three zebra bars on the asphalt, with the south frontage and the hero colonnade behind |
+| 14 | `demo/review-demo-north-buildings.png` | [<img src="demo/review-demo-north-buildings.png" alt="north buildings" width="180">](demo/review-demo-north-buildings.png) | Demo | across the Blvd | North-side buildings (TCL, Tussaud's) seen from the south side across the road |
 
 ## Scene conventions