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 by Tools/export_block_frontage.py,
imported to /Game/Hollywood/Frontage/ and staged by the demo builder with the
look material set (stone for the theatres, stucco for the retail run).

Adding neighbours exposed a pre-existing placement bug that was invisible while
the hero facade stood alone in an empty field:

- UE south is +Y here (south sidewalk Y +718..+1447), but the hero sat at
  Y -1450 on the NORTH side of the street.
- It was also at X -12024..-9420, 26 m east of the 6840 footprint; the frontage
  gap between 6902 and 6838 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; the frontage
and north-building exporters no longer apply 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 silhouetting.

Result: the demo is a street - continuous south frontage with the hero in it,
both sidewalks, the road with the designated crossing, and the north-side
buildings across the road.

Screenshots re-rendered and approved by the owner.

Squash of branch frontage-block-0.1.0 (PR #6).

Screenshots/README.md

@@ -23,8 +23,8 @@ 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.
+All shots ☑ approved 2026-11-07, including the block frontage pass that added
+the neighbouring buildings and corrected the hero and north-building placement.
 
 | # | File | Preview | Map | View | What it shows |
 | --- | --- | --- | --- | --- | --- |
@@ -38,10 +38,10 @@ 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