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.

Tools/README.md

@@ -18,6 +18,8 @@ Geographic tools live in [`Geo/tools/`](../Geo/README.md) and the Blender-side b
 | `check-lfs.sh` | Fails if the `lfs` filter is missing or an LFS-tracked file was committed as a plain blob |
 | `facade_kit_build.py` | Builds the reusable façade **module kit** at the measured 4.96 m bay: pilaster, sill, lintel, window bay (surround + glazing), shopfront bay (piers, glass, fascia), door bay (jambs, door, threshold), cornice and parapet + coping. Exports each piece with the shared preset plus a JSON part report (dims + evidence per piece). |
 | `ue_import_facade_kit.py` | Imports the kit into `/Game/Hollywood/Kit/*` as static meshes with complex-as-simple collision; writes `/tmp/gigline/kit-import.txt`. |
+| `theatre_trim_build.py` | El Capitan Theatre trim: projecting marquee canopy, illuminated fascia, recessed soffit, vertical blade sign with frame and bracket. Built **in world coordinates** (span and pavement height baked in) with a JSON part report, so staging is a single spawn at the origin. |
+| `ue_stage_theatre_trim.py` | Imports the trim to `/Game/Hollywood/Theatre` and stages one actor per piece in the DemoMap with site materials; clears a previous run first. |
 | `ue_apply_facade_kit.py` | Lays the kit over a building's street face from its own bounding box: bay count = round(width / 4.96), storeys from the height, shopfronts on the ground floor, windows above, pilasters on bay boundaries, cornice and parapet at the top. Clears a previous application first; unique labels per building. |
 | `generate_facade_textures.py` | Deterministic stdlib PNG generator for the facade maps (`T_StoneAshlar`, `T_Stucco`, `T_Asphalt`, `T_Concrete`, each `_BC` base colour + `_R` roughness). Pure-zlib writer, hash-based value noise, identical bytes on every run; `--size` and `--out` (`/tmp/gigline/textures` by default). `ue_build_demo_map.py` imports them into `/Game/Hollywood/Textures` and samples them world-aligned. |
 | `ue_common.py` | Shared helpers for the Unreal commandlet scripts: `make_writable()` clears the read-only bit an LFS `.umap` checks out with (otherwise `save_map()` returns False silently), and `require_saved()` makes that failure explicit. |