fix(tools): importers clear the read-only LFS bit before saving; docs refresh

0.1.3 packaging and setup fixes from what 0.1.x actually exposed.

- New Tools/ue_common.py: make_writable() clears the read-only bit an LFS .umap
  checks out with (save_map() otherwise returns False silently and the staged actor
  is lost) and require_saved() makes that failure visible. ue_hero_facade_import and
  ue_import_north_buildings now call it; the map builders already did. Verified from
  a forced 0o444 map: chmod logged, save_map True, exit 0.
- Docs/build.md: pipeline table now lists the seven site FBXs plus frontage, north,
  hero and map steps and the shared FBX preset; packaging archive corrected to
  Builds/GigLineQA; packaged-log location and -qaselftest usage documented; new
  'Traps that cost real time in 0.1.x' table (read-only save, hero --out is the FBX,
  MPFB add-on path, shot actor quitting under QA, null-RHI trace trap).
- Docs/setup.md: fresh-checkout build marked verified 2026-11-08 and the blocker
  closed; new optional-keys section for OPENROUTER_API_KEY and MAPBOX_ACCESS_TOKEN
  (gitignored .env, not needed by build/tests/release).
- Docs/Architecture 07 + architecture.md: build-output path corrected, marked
  outside the repository.
- 5 new tests for ue_common (54 total).

Docs/odbl-review.md

@@ -37,22 +37,12 @@ Important nuance: ODbL governs the **database** (the OSM data as a collection an
 
 ## 4. Decision: posture for the derived geometry
 
-The OSM-derived block geometry (streets, footprints, sidewalks) is treated as a
-**Produced Work / derivative database** of the OpenStreetMap database.
+The OSM-derived block geometry (streets, footprints, sidewalks) is treated as a **Produced Work / derivative database** of the OpenStreetMap database.
 
-- The **share-alike obligation is accepted for the data layer only**. The
-  release must carry: (a) the on-screen attribution (implemented), (b) the ODbL
-  link (implemented), and (c) an offer of the OSM source for the geometry —
-  satisfied by the committed raw extract plus its manifest.
-- **Project creative work (code, shaders, artist-authored façades, textures) is
-  NOT under ODbL.** It remains project-owned CC0 (see `LICENSE`) and carries no
-  share-alike obligation. Only geometry that can be argued to encode OSM
-  database facts (streets, building footprints, sidewalk layouts) is in scope.
-- **No new obligation is created by the DEM**: 3DEP is US Government public
-  domain and is independent of ODbL.
-- **Do not** import OSM imagery/panoramas as textures (OSM map tiles or aerial
-  imagery are separately licensed); the project already treats OSM as layout
-  only (`Docs/licensing.md` rule 3).
+- The **share-alike obligation is accepted for the data layer only**. The release must carry: (a) the on-screen attribution (implemented), (b) the ODbL link (implemented), and (c) an offer of the OSM source for the geometry — satisfied by the committed raw extract plus its manifest.
+- **Project creative work (code, shaders, artist-authored façades, textures) is NOT under ODbL.** It remains project-owned CC0 (see `LICENSE`) and carries no share-alike obligation. Only geometry that can be argued to encode OSM database facts (streets, building footprints, sidewalk layouts) is in scope.
+- **No new obligation is created by the DEM**: 3DEP is US Government public domain and is independent of ODbL.
+- **Do not** import OSM imagery/panoramas as textures (OSM map tiles or aerial imagery are separately licensed); the project already treats OSM as layout only (`Docs/licensing.md` rule 3).
 
 Release checklist items this lands:
 
@@ -63,20 +53,13 @@ Release checklist items this lands:
 
 ## 5. Remaining (tracked separately)
 
-- **Blosm add-on licence** is still `pending` in THIRD_PARTY_NOTICES (tool-only,
-  not distributed — must be checked once, not a release blocker for ODbL).
-- Façade signage/trademarks: separate rights from the photograph, own the
-  geometry; not an ODbL question (see THIRD_PARTY_NOTICES "Reference
-  photography" rules).
+- **Blosm add-on licence** is still `pending` in THIRD_PARTY_NOTICES (tool-only, not distributed — must be checked once, not a release blocker for ODbL).
+- Façade signage/trademarks: separate rights from the photograph, own the geometry; not an ODbL question (see THIRD_PARTY_NOTICES "Reference photography" rules).
 
 ## 6. Sources checked
 
 - ODbL text: <https://opendatacommons.org/licenses/odbl/1-0/>
 - OSM licence summary: <https://www.openstreetmap.org/copyright>
-- ISPRS/ODbL practice notes on derived game geometry from OSM footprints
-  (objective standard: attribution + produced-work offer, share-alike limited
-  to the data layer).
+- ISPRS/ODbL practice notes on derived game geometry from OSM footprints (objective standard: attribution + produced-work offer, share-alike limited to the data layer).
 
-Not reviewed here (out of scope for this item): engine redistribution terms
-(Epic), MPFB asset terms, street-prop reuse terms — all tracked in
-`THIRD_PARTY_NOTICES.md`.
+Not reviewed here (out of scope for this item): engine redistribution terms (Epic), MPFB asset terms, street-prop reuse terms — all tracked in `THIRD_PARTY_NOTICES.md`.