All Cargo.toml files, empty lib.rs/main.rs stubs, .cargo/config.toml, rustfmt.toml.
Acceptance criteria:
- cargo build --workspace compiles clean
- cargo clippy --workspace -- -D warnings passes
- cargo fmt --all --check passes
- Zero external crate dependencies
- All inter-crate path dependencies wired per the dependency graph in CLAUDE.md
This is done — landed in the initial commit.