Implement deterministic specification validation and relationship checks

Plan ID

EM-03

Purpose

Implement the deterministic validation engine that protects the specification store from malformed or inconsistent records.

Scope

• Validate all six EARS pattern forms using the accepted keyword-based rules.
• Validate required fields, stable IDs, applicability selectors, provenance, and verification metadata.
• Resolve interface and requirement references.
• Enforce relationship vocabulary, bidirectional symmetry, and acyclic depends-on and supersedes graphs.
• Validate artifact registry paths, digests, owners, and allowlisted validator names without executing caller-supplied commands.
• Return structured diagnostics with stable codes, locations, and remediation data.

Dependencies

Depends on EM-02. The logical schema and storage format are already settled by ADR-0001 and ADR-0002.

Acceptance criteria

• Valid fixtures pass all checks.
• Invalid fixtures cover each required-field, EARS, reference, symmetry, cycle, path, digest, and schema-version failure.
• Validation never mutates the working tree.
• Diagnostics are deterministic in ordering and machine-readable form.
• Tests distinguish specification validation from WMS lifecycle Validation Rules.

Out of scope

CLI wiring belongs to EM-04. Semantic impact judgment remains outside the validator.