Merge branch 'gameplay-crossing-0.1.0': designated street crossing + review map fixes

MEMORY.md

@@ -152,3 +152,25 @@ Scope: facts and traps that cost time to establish. Planned work lives in [TODO.
 
 - `Tools/judge_screenshot.py` — runs an OpenRouter vision model over a screenshot vs an expected-scene description. Reads `OPENROUTER_API_KEY` from the repo `.env` (ignored). Base64 data-URI image under `image_url.url`; OpenAI-compatible body → `POST /api/v1/chat/completions`. `openai/gpt-4o-mini` returns a `{verdict, confidence, reason, missing}` JSON. It flags genuinely missing content (e.g. `main`'s pre-warm-skin character shot judged "no"); it is a pre-check, not the human verdict.
 - Test one: `Tools/judge_screenshot.py --image Screenshots/review-01-character.png --expect "<scene>" --verbose`. Bulk: `--shots` (parses the README rows).
+## 2026-11-07 — Blender skill packs: discovery depth
+
+- **The 94 packs were never registered with the `skill` tool**, only readable as files. The loader resolves `<skills-root>/<pack>/SKILL.md` one level down; `.agents/skills/blender-skills/` is a *container* of 94 packs, so it was skipped silently (no warning, no error). Symptom: `skill("archviz")` unresolvable even though `archviz/SKILL.md` exists.
+- **Fix applied:** 94 symlinks in `~/.agents/skills/<pack>` → `<repo>/.agents/skills/blender-skills/<pack>/`. The catalog then lists all of them (verified by calling `skill` on `collision-proxy`: base dir resolves through the link). `references/` stays unlinked — it is a shared folder with no `SKILL.md`, not a pack.
+- **The AGENTS.md "MCP-driven" caveat is overstated.** 41 of 94 SKILL.md mention MCP, mostly only in the `description` line; the bodies are method guides (naming, proportions, validation checklists) that work headless. Do not skip a pack because it advertises MCP.
+- **Skill names in AGENTS.md/TODO.md all resolve** except `references`, which is the folder above, not a pack.
+- Symlinks are user-level: a fresh machine needs the same 94 links before the packs are loadable by name.
+- **A shared checkout can commit your uncommitted edit for you, or lose it.** This entry was written but not yet committed when another session ran a `git commit` that included `MEMORY.md`; it landed inside their commit (`54b6239`) with a message that does not mention it. Had they overwritten the file instead, the work would have been gone with no reflog to recover from. On a shared worktree, either commit a shared file immediately or check `git log -S` for it before assuming the edit is missing.
+
+
+## 2026-11-07 — Street visibility and the LFS lockable trap
+
+- **Every street surface (road, sidewalks, kerbs, markings) had 100 % downward face normals** — `strip()`'s natural winding (rows along +s, cols along +normal) faces the ground. Invisible in engine for as long as the terrain covered them; the corridor cut exposed the black trench. Fixed by reversing the winding in `strip()`, `kerb_faces()` and `crossing_band()`.
+- **`*.blend` and `*.umap` are LFS-lockable in `.gitattributes`** — Git LFS checks them out read-only (444). `bpy.ops.wm.save_as_mainfile` then fails ("path is not writable") and `EditorLoadingAndSavingUtils.save_map` silently returns False. All Blender builders now chmod u+w before saving and treat a failed save as fatal; the UE map builders chmod the .umap first. A failed save used to leave downstream steps building from stale files — that produced a degenerate-mesh FBX (all-same vertex indices from an index-arithmetic bug) that cost an hour to trace.
+- **FBX SDK refuses to triangulate the crown-twisted crossing quads** ("unable to triangulate mesh ... will be omitted") — emit triangles from the builder, and make sure per-stripe vertex indices advance (`len(verts)` must be captured before the loop, not per-corner).
+- Demo-map coordinate note: UE Y is south-positive; the facade at Y −1450 and the player start at Y −3500 are on opposite sides of the road (Y −1382..+1047) — arrangement is correct; the Sidewalk_North/South mesh names are swapped relative to their physical sides (documented in export_site_fbx.py).
+
+## 2026-11-07 — ReviewMap corruption: deprecated level calls + save-order bug
+
+- **`EditorLevelLibrary.load_level`/`new_level` are deprecated no-ops in `-nullrhi` commandlets** (they return without switching worlds, so staged actors land in whatever world is current and get saved over the wrong map). Use the `LevelEditorSubsystem`: `unreal.get_editor_subsystem(unreal.LevelEditorSubsystem).load_level(path)` actually switches. Symptom was ReviewMap containing Demo actors + `ShotSequencer`.
+- **Map-save ordering bug in `Tools/ue_build_review_map.py`**: the script saved ReviewMap *after* the DemoMap section, but the switch back to ReviewMap fails silently because the map only exists in memory at that point — so the final `save_map` wrote the demo world over ReviewMap. Fix: save ReviewMap first, then stage the demo cameras, and never switch back. Both maps verified by probe (ReviewMap lists Review actors; DemoMap lists Demo actors).
+- Rebuilt ReviewMap after the fixes: character, both cubes (A grounded, B floating at 2 m), pawn, NPC prefab, hero facade all present; user re-approved the shots. README cube naming corrected (README had A/B swapped vs the script).