docs: bring setup and toolchain in line with a finished bootstrap

Initial setup is complete: setup.md opens with a per-section status table and
drops the stale blockers, toolchain.md records that every pin has been exercised
on real work (engine compile + package, Blender/MPFB/Blosm assets, PROJ origin),
and MPFB's load-and-export check moves from pending to verified. Records the one
unexercised path — a fresh checkout — as a v0.1.0 release check.

MEMORY.md

@@ -65,3 +65,9 @@ Scope: facts and traps that cost time to establish. Planned work lives in [ROADM
 - **Flatpak Blender headless needs `XDG_CONFIG_HOME=$HOME/.var/app/org.blender.Blender/config`** for extensions: `bpy.utils.user_resource('EXTENSIONS')` otherwise resolves to `~/.config/blender/5.2/extensions` (empty) and `bl_ext.blender_org.mpfb` is undiscoverable. Blosm unaffected (scripts/addons via `BLENDER_USER_SCRIPTS`). Found via `Tools/addon_compat_probe.py`; documented in `Art/blender/README.md`.
 - **UE 5.8 Interchange skips material/texture assets for skeletal FBX imports** (static imports do get materials). Finish the chain in Python: import texture, build Material via `MaterialEditingLibrary`, assign with `sm.set_editor_property('materials', [SkeletalMaterial])` — the struct field is `material_interface`, not `material`, and `SkeletalMesh.set_material()` does not exist. See `Tools/ue_character_import.py`.
 - **Blender 5.2 FBX exporter removed `armature_nla`** (passes for 4.x recipes fail). Also: a baked image is only referenced by the FBX exporter when `image.filepath` (not just `filepath_raw`) is set and the exporter can map the node — MPFB's v2 skin node-group tree can't be mapped, so a flat export material is required.
+
+## 2026-11-07 — Collaboration and scope
+
+- **Two sessions edit this repo at once.** The other session created the Unreal project and the blank package while this one was documenting. Check `git log` and `git status` before committing, and never `git add -A` blindly: it once swept generated `Game/GigLine/Build/**` logs into a commit. Stages the source files deliberately.
+- **`Build/` under a project is generated**, not source — `FileOpenOrder/*.log` and packaging output. `.gitignore` now covers it alongside `Binaries/`, `Intermediate/`, `Saved/`, `DerivedDataCache/`.
+- **Scope boundary for `0.1.0`:** do not tag `v0.1.0` without an explicit go-ahead from the owner. It is a minor release and carries the walking/driving demo promise; the board's release checks decide when it is ready, not the pace of work.