feat(theatre): marquee canopy and blade sign; fix two placement bugs

Tools/theatre_trim_build.py builds the El Capitan Theatre's signature features in
world coordinates - projecting marquee (12.0 x 2.60 m canopy, 4.60 m soffit),
illuminated fascia, recessed soffit, vertical blade sign (1.30 x 5.20 m) with frame
and bracket - with a JSON part report. Tools/ue_stage_theatre_trim.py imports and
stages one actor per piece with site materials, clearing a previous run first.

Two bugs, neither visible in a render:
- Axis sign: Blender +Y is Unreal -Y, so the theatre face at Unreal Y +1001 is
  Blender Y -10.01; using +10.01 mirrored the marquee across the boulevard.
- Absolute Z: trim heights ignored the 4.56 m pavement, leaving the canopy 5 cm above
  the ground. GROUND_Z now offsets every height.

QA wall probe: the Y 1000 scan row sat ~1 cm from the building line and grazed the
theatre wall after the kit's proud shopfronts; rows now sample the street envelope
only. Packaged QA back to PASS (transect 0 holes, wall probe 0/35, facade probe 0/9).
Screenshots re-rendered and verified 4/4.

TODO.md

@@ -20,7 +20,7 @@ Suggested blender skills: **procedural-modeling** + **geometry-nodes** (the faç
 - [A] **Replace placeholder materials.** **In progress 2026-11-09.** `ensure_material()` now builds masonry coursing (world-space course height + joint band + tint, corrected for UE's centimetre WorldPosition) and roughness variation; new `M_FacadeStoneShadow`, `M_FacadeGlass` (specular 0.62 ≈ IOR 1.5 without a refraction pass) and `M_FacadeBanner`; assignment is per **slot** keyed on the imported slot name (it was slot-0 only, which on the hero is the banner, so stone/glass/shadow were still flat). Hero: 4/4 slots, frontage and north buildings 2/2. Remaining: bake real texture maps (brick/stone/asphalt generators) rather than graph-only detail, and give the frontage shopfront line its own material.
 - [x] **Give OSM buildings a façade style.** **Closed as superseded 2026-11-09.** The Blosm `setupScript` route would build a second, competing façade system next to the module kit defined in the previous task. The kit already gives every staged building a real elevation (shopfront line, window rhythm, pilasters, cornice, parapet) from a single module, so a Blosm style script would duplicate it with a different vocabulary and a different set of assumptions. Revisit only if the kit cannot express a building the photographs demand.
 - [ ] **Hero façade detail pass.** Ionic capitals and fluting, the parapet motto band and medallions as geometry or decal, window rhythm behind the colonnade, and the three portal flights at their photographed proportions.
-- [ ] **El Capitan Theatre (6838) and the retail neighbours.** Model from the 18-frame 5472×3648 reference set; the theatre shares the measured 4.96 m bay rhythm with the temple.
+- [A] **El Capitan Theatre (6838) and the retail neighbours.** **Theatre trim done 2026-11-09:** `Tools/theatre_trim_build.py` builds the features that make the building read as itself — projecting marquee (12.0 × 2.60 m canopy at a 4.60 m soffit), illuminated fascia, recessed soffit, and a vertical blade sign (1.30 × 5.20 m) with frame and bracket; `Tools/ue_stage_theatre_trim.py` imports and stages it with site materials. Two bugs fixed en route: the trim was mirrored to the far side of the boulevard (Blender +Y is Unreal −Y) and the marquee sat 5 cm above the pavement (absolute Z where the pavement is 4.56 m above the datum). **Still open:** the retail neighbours modelled from the 18-frame reference set.
 - [ ] Review every façade change with `Tools/render_screenshots.sh` before tagging.
 - [ ] Tag `v0.1.4` and write `CHANGELOG.md` entry; then remove this section.