chore: scaffold repository and record 0.1.0 setup state

Create Game/, Art/, Geo/, Tools/, Docs/ with LFS and ignore rules, record the
workstation audit, toolchain pins, setup checklist, release checks, and
licensing policy. ROADMAP 0.1.0 environment tasks marked to match verified state.

Game/README.md

@@ -0,0 +1,18 @@
+# Game
+
+The Unreal project lives at `Game/GigLine/GigLine.uproject` once created. Nothing here yet.
+
+## What gets committed
+
+- `Config/` — engine and project settings, including the quality presets used for release checks
+- `Source/` — C++ modules
+- `Content/` — `0.1.0` map, materials, meshes; LFS-tracked
+- `GigLine.uproject`
+
+## What does not
+
+`Binaries/`, `Intermediate/`, `Saved/`, `DerivedDataCache/` — all generated. `.gitignore` covers them; do not add exceptions.
+
+## Engine
+
+Installed outside the repository. Its path and exact version are recorded in [../Docs/toolchain.md](../Docs/toolchain.md). Nothing in this directory may assume a machine-specific engine path; the documented build procedure is [../Docs/build.md](../Docs/build.md).