Publish contributor automation kit

[VivienP]

What changed

• replaces the root engineering contract with docs/engineering_contract.md and turns AGENTS.md into a concise tool-neutral router
• adds three canonical repository skills with byte-identical Claude mirrors
• adds two read-only role specifications with thin Codex and Claude adapters
• adds a deterministic agentic-layer validator, regression tests, and explicit CI gates
• aligns public MDR/IVDR scope and adjudication limitations across the documentation
• pins the byte-compared third-party inventory to LF for reproducible Windows checkouts

Why

The repository exposed contributor instructions without publishing the reusable roles, skills, compatibility boundaries, or deterministic validation needed to make that layer usable after cloning.

Impact

The product CLI, verification runtime, audit artifacts, and schemas are unchanged. Contributors gain a public, repository-local automation kit with fail-closed validation and documented trust boundaries.

Validation

• python -m pytest -q: 584 passed, 1 skipped
• python -m ruff check src tests scripts: passed
• python -m mypy src/locuslab: passed for 48 source files
• python scripts/check_project_state_docs.py --check: passed
• python scripts/check_agentic_layer.py --check: passed
• clean source export of commit aba65a5: the same five gates passed
• public demo executed twice: 11 artifacts were byte-identical, manifest hashes were valid, and DOCX/XLSX/JSON/JSONL artifacts opened successfully

Compatibility limits

Static compatibility is CI-enforced. The recorded Codex release-skill smoke passed fail-closed; custom reviewer spawning remains blocked in the observed Codex CLI version, and Claude Code was unavailable for a live smoke. These limitations are recorded in docs/agentic/README.md and are not presented as demonstrated multi-client support.