geo: one tool directory, one unit boundary, per-asset provenance

Geo/tools/ is now every geographic script, with Geo/README.md documenting each
one; the Blender-side builders moved beside their outputs in Art/blender/*/ and
import their helpers from Geo/tools/osm_common.py.

That module gains to_unreal_local() and to_blender_local(): the only place in the
repository that multiplies metres by 100, so a second silent scale cannot be
introduced. block_height_report.py adds height provenance for the block — 3 of
15 buildings have no height data and render at a placeholder 6.4 m.
asset_metadata.py writes and audits <asset>.geo.json sidecars; four now exist
(hero-facade, terrain, street, blockout) and the audit recomputes each centre from
the origin, failing anything that disagrees.

Geo/tools/block_height_report.py

@@ -0,0 +1,75 @@
+#!/usr/bin/env python3
+"""Report which block buildings have real height data and which are guesses.
+
+Usage:
+    Geo/tools/block_height_report.py Geo/raw/osm-api-map-2026-11-06.osm
+
+`height` and `building:levels` are the only height evidence OSM carries. Where
+neither exists, Blosm falls back to `defaultLevels * levelHeight`, which is a
+placeholder: the demo renders a constant-height block instead of a real skyline.
+This tool lists every building in the demo bounds with its height source, so the
+substitutions are visible and measurable rather than buried in the model.
+
+Exit code is 0 either way; the count of guessed buildings is the deliverable.
+"""
+
+import argparse
+import math
+import sys
+
+import osm_common as oc
+
+LEVEL_HEIGHT = 3.2
+
+
+def main():
+    ap = argparse.ArgumentParser()
+    ap.add_argument("osm")
+    args = ap.parse_args()
+    nodes, ways = oc.load(args.osm)
+
+    line, lat0, lon0, lengths, block_len = oc.block_extent(
+        nodes, ways, "Hollywood Boulevard", "North Orange Drive", "North Highland Avenue")
+
+    def in_block(pts):
+        if min(p[1] for p in pts) > line[-1][1] or max(p[1] for p in pts) < line[0][1]:
+            return False
+        return True
+
+    rows = []
+    for wid, tags, refs in ways:
+        if "building" not in tags:
+            continue
+        pts = oc.way_points(nodes, refs)
+        if not pts or not in_block(pts):
+            continue
+        tag_height = tags.get("height")
+        levels = tags.get("building:levels")
+        if tag_height:
+            height, source = float(tag_height), "height tag"
+        elif levels:
+            height, source = float(levels) * LEVEL_HEIGHT, f"levels x {LEVEL_HEIGHT} m"
+        else:
+            height, source = 2 * LEVEL_HEIGHT, f"GUESS: default 2 levels x {LEVEL_HEIGHT} m"
+        nearest = min(oc.project(p, line, lat0, lon0, lengths)[0] for p in pts)
+        side = "S" if oc.project(pts[0], line, lat0, lon0, lengths)[2] < 0 else "N"
+        rows.append((side, nearest, wid, tags.get("name", "") or tags.get("addr:housenumber", ""),
+                     height, source))
+
+    rows.sort(key=lambda r: (r[0], r[1]))
+    guessed = [r for r in rows if r[5].startswith("GUESS")]
+    print(f"{len(rows)} buildings in the block, {len(guessed)} with a guessed height\n")
+    for side, setback, wid, name, height, source in rows:
+        flag = "  <-- guessed" if source.startswith("GUESS") else ""
+        print(f"{side} way {wid:>10}  setback {setback:5.1f} m  height {height:5.1f} m  "
+              f"({source:26})  {name[:34]}{flag}")
+
+    if guessed:
+        print("\nGuessed heights to replace from the reference photography:")
+        for side, setback, wid, name, height, source in guessed:
+            print(f"  {side} way {wid} {name}")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())