chore: Phase 0 sign-off — all acceptance criteria met

[digital-michael]

Purpose

Checklist issue to confirm all Phase 0 acceptance criteria (per Project Charter §8.1) are met before opening Phase 1 work.

Phase 0 checklist

• chore: verify and configure branch protection rules for main and dev #2 — Branch protection on main and dev verified
• chore: set up GitHub Actions CI matrix for all platforms #3 — CI matrix created and green on all platforms
• chore: register self-hosted CI runners (macOS and Linux/Wayland) #4 — Self-hosted runners registered (macOS + Linux/Wayland)
• chore: verify local build on Fedora 43 / Wayland (unmodified fork) #5 — Local build verified on Fedora 43 / Wayland (no errors)
• chore: establish and document performance baseline (pre-modification) #6 — Performance baseline measured and committed to doc/perf-baseline.md
• docs: add GOVERNANCE.md — maintainer roles, PR process, phase gates #7 — GOVERNANCE.md merged
• docs: add CODE_OF_CONDUCT.md (Contributor Covenant v2.1) #8 — CODE_OF_CONDUCT.md merged
• docs: add CONTRIBUTING.md — PR workflow, branch conventions, test requirements #9 — CONTRIBUTING.md merged
• chore: update source file license headers to GPL-2.0-or-later #10 — License headers updated to GPL-2.0-or-later
• chore: add upstream remote (input-leap/input-leap) and document sync workflow #11 — Upstream remote documented

Gate criteria (from charter §8.1)

• CI green on all platforms (Linux + Windows + macOS)
• Zero failing tests on main
• Performance baseline committed and linked here
• README and PROJECT_CHARTER.md present in repo ✓ (done)
• Branch protection active on main and dev

On completion

Close this issue and create the Phase 1 project / milestone.