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.

Docs/build.md

@@ -0,0 +1,21 @@
+# Build
+
+Fresh-checkout build procedure. To be completed once the pinned engine is installed and a blank project has been packaged — see [setup.md](setup.md). Until then this file records only the constraints that are already known.
+
+## Constraints
+
+- Engine installation is external to the repository. Record its path and exact version in [toolchain.md](toolchain.md).
+- Build output (`Binaries/`, `Intermediate/`, `Saved/`, `DerivedDataCache/`) is never committed.
+- Large content is LFS-tracked, so a fresh clone needs `git lfs install && git lfs pull` before any build.
+
+## Procedure (placeholder)
+
+```bash
+git clone <remote> gig-line && cd gig-line
+git lfs install && git lfs pull
+# engine path, project generation, build, and packaging commands — fill in after setup
+```
+
+## Packaged Linux build
+
+Record here: the packaging command, output path, size, and the controls document path. The packaged build must launch and quit cleanly on the development workstation before `v0.1.0` is tagged.