Phase 0 — Foundation

Status: complete (2026-05-22). 10 PRs landed; Phase 0 issues #4–#12 closed.

Phase 0 had one mission: make the repository’s skeleton build cleanly on green CI, so feature work in later phases never drags build-system fights into every PR.

What landed

In dependency order:

1. Pinned the Rust toolchain (1.83.0) so Corrosion finds it deterministically, and unblocked the broken seed skeleton (empty Cargo.toml, phantom .cpp refs, BUILD_TARGET_SOC → BUILD_TARGET_KPU rename; Corrosion bumped to fix a rustc --version parse bug).
2. Style enforcement — .clang-format (LLVM base, 4-space, 120 columns), .editorconfig, and ADR-0001 (third-party license audit).
3. CMake presets — sitl-debug, sitl-release, kpu-cross, wsl2-sitl (Ninja single-config; per-preset binary dir).
4. Cross-toolchain — cross-toolchain.cmake for aarch64 KPU cross-compile, and the CI job re-enabled.
5. FetchContent dependencies — MTL5, Universal, yaml-cpp, Catch2, Tracy, stb (all pinned).
6. sccache — compiler caching for Rust + C++ (warm-cache: ~73% SITL, ~50% KPU-cross hit rates).
7. Lint job — clippy + cargo fmt + clang-format.
8. Release flow — commitlint + release-please for Conventional-Commits-driven SemVer.
9. Dev bootstrap — idempotent bootstrap.sh / bootstrap.ps1 for new-dev setup.

Conventions ratified

These are the project-wide rules still in force:

• PR-only, even solo — no direct commits to main; every change goes through a PR with green CI.
• Branch = <cc-type>/<slug>, PR title = Conventional Commits message, squash-merge, commitlint-enforced.
• Claude opens a ready PR, waits for green CI + CodeRabbit, and stops; a human merges. No auto-merge.

Explicitly deferred

No algorithm code, no real cxx bridge (the stub was deleted — the real one is Phase 1), no KPU broker/IPC, no live release tag, no docs site (that’s Phase 11 — this site). Phase 0 only set conventions and stub interfaces.

Companion: docs/arch/phase0-foundation/README.md.