Implement the `ears-manager` core CLI

Scope

Implement the first statically linked Go ears-manager binary using the accepted one-file-per-record YAML format and the reviewed logical schema.

Start with the smallest useful commands: project/check validation, requirement add/list/show/update/retire, interface add/list/show, artifact get/put, and deterministic JSON diagnostics. Include the CLI help/exit-status contract from #30 and time-box the Q18 interface-specification decision inside this work.

Dependencies

• #46 and PR #61 schema review.
• #30 CLI integration contract.
• ADR-0001 storage format.

Acceptance criteria

• Canonical YAML output is deterministic and safe-loader validation rejects malformed records, dangling references, invalid EARS patterns, and relationship cycles.
• JSON output and non-zero exit statuses are stable and documented.
• Golden fixtures cover valid records, invalid records, retirement, and cross-reference failures.
• The binary builds without a runtime dependency on the host language environment.

Start with the schema review in #46 and PR #61, the CLI integration contract in #30, and ADR-0001 on storage format. Identify the required command and validation entry points, then use golden fixtures for valid, invalid, retired, and cross-reference cases. Done means a statically linked binary with deterministic YAML and JSON behavior, documented exit statuses, and no host-language runtime dependency.