docs: bring every document in line with the current build

README rewritten around the actual state (walkable DemoMap, blockout facades,
planned patches); Tools/README now lists all seventeen tools by role; build.md
gains the content pipeline table and the two enforced rules (one unit conversion,
collision decided at import). Setup gains a content-pipeline row, the toolchain
state notes the demo level exercises the engine path, release checks record the
Blender pre-check that backs traversal, PLAN points at ROADMAP/MEMORY/Screenshots,
and THIRD_PARTY_NOTICES gains rows for the hero facade and the candidate props.

Also fixed the last stale reference to Geo/scripts in MEMORY.md - a sweep found
old paths in six documents after the tool move, which the memory entry now warns
about.

Docs/build.md

@@ -68,6 +68,34 @@ Both content-acceptance tests run headless and are the template for all asset im
 # Note: 5.8 swallows Python print() in the commandlet; scripts write result files to /tmp.
 ```
 
+## Content pipeline (current)
+
+The hero block and the demo level are built by a fixed sequence. Each step writes
+a result file under `/tmp/gigline/`; read it, because the commandlet's own stdout
+can be swallowed.
+
+| Step | Tool | Output |
+| --- | --- | --- |
+| OSM blockout | `Art/blender/blockout/blosm_blockout.py` | `Art/blender/blockout/blockout-*.blend` |
+| Terrain | `Art/blender/terrain/terrain_from_dem.py` | `Art/blender/terrain/terrain-*.blend` |
+| Street | `Art/blender/street/street_mesh.py` | `Art/blender/street/street-*.blend` |
+| Site assembly | `Art/blender/site/site_assembly.py` | `Art/blender/site/site-*.blend` |
+| Site export | `Art/blender/site/export_site_fbx.py` | six FBXs, one per mesh |
+| Hero façade | `Tools/hero_facade_build.py` | `Art/blender/hero/hero-facade-*.blend` + JSON report |
+| Site import | `Tools/ue_import_site.py` | `/Game/Hollywood/Site/*` |
+| Hero import | `Tools/ue_hero_facade_import.py` | `/Game/Hollywood/ElCapitan/SM_HeroFacade` |
+| Demo map | `Tools/ue_build_demo_map.py` | `/Game/Hollywood/DemoMap` |
+| Review shots | `Tools/ue_build_review_map.py` + `Tools/render_screenshots.sh` | `Screenshots/` |
+
+Two rules that the pipeline enforces rather than documents:
+
+- **One conversion.** Metres to Unreal centimetres happens only in
+  `Geo/tools/osm_common.py::to_unreal_local`. Sidecars (`<asset>.geo.json`) record
+  the result and `Geo/tools/asset_metadata.py audit` re-derives it.
+- **Collision is decided at import,** not later: terrain, road and sidewalks are
+  complex-as-simple; kerbs and props stay simple. A simple hull over a kerbed
+  street ramps straight across the kerb.
+
 ## Known engine quirks (2026-11-07)
 
 - One handled `PSOPrecache` ensure fires at packaged-build exit only; not blocking.