feat: implement repo command-family parity

[Ismail-elkorchi]

Acceptance Criteria

• Add Repo.repoInfo() parity for git repo info --format=keyvalue outputs.
• Add Repo.repoStructure() parity for git repo structure --format=keyvalue outputs.
• Mark repo command family as implemented in roadmap and parity matrix.
• Enforce implemented-state evidence checks for repo in scripts/parity_matrix_check.

Checklist

• node scripts/check --runtime=node
• node scripts/check --runtime=deno
• node scripts/check --runtime=bun
• npx jsr publish --dry-run --allow-dirty --config jsr.json

Simulated Role Reviews

Product review

Findings:

• The remaining user-visible parity gap after last-modified was repo command family coverage.
  Changes made:
• Added repoInfo and repoStructure API operations.
• Updated command-family status to implemented for repo.
  Evidence pointers:
• src/index.ts
• docs/parity-matrix.md
• spec/parity-roadmap.yaml

QA review

Findings:

• Parity claims needed executable CLI baseline comparisons for both repo subcommands.
  Changes made:
• Added tests for git repo info --format=keyvalue parity.
• Added tests for git repo structure --format=keyvalue parity.
  Evidence pointers:
• tests/node/repo-command-family.test.mjs

Security review

Findings:

• src runtime policy disallows process spawning in production code.
  Changes made:
• Implemented repo metrics using in-process object/ref traversal.
• Reused existing safe object parsing paths and validation.
  Evidence pointers:
• src/index.ts
• src/core/repo/repo-command.ts

Performance review

Findings:

• Structure metrics can revisit objects across multiple refs unless deduplicated.
  Changes made:
• Added queue traversal with a seen set to avoid duplicate object parsing.
• Kept traversal bounded to reachable refs only.
  Evidence pointers:
• src/index.ts

Maintainer review

Findings:

• Implemented-state transitions require machine-checkable evidence gates in the same change.
  Changes made:
• Added repo evidence assertions to scripts/parity_matrix_check.
• Added API docs and parity documents updates in one PR.
  Evidence pointers:
• scripts/parity_matrix_check
• docs/api.md
• docs/parity-matrix.md
• spec/parity-roadmap.yaml