Mergen 2.1.0

[2.1.0] - 2026-07-25

Added

• Independent milestone verification is now the primary Mergen product identity.
  The standalone mergen-supervise entry point consumes externally produced
  verification evidence, reproduces deterministic checks, applies the Governor
  risk floor, and returns a fail-closed advancement decision without owning the
  external implementation workflow.
• The versioned milestone decision 1.1 contract with pass, conditional_pass,
  fail, and unverifiable verdicts, plus the corresponding advance,
  human_review_required, return_for_remediation, and hold actions.
• Evidence classes, fresh deterministic reproduction, source-state and decision
  hashes, exact-report human approval binding, Markdown rendering, professional
  issue forms, support guidance, contribution guidance, and verification-focused
  security documentation.

Changed

• The existing specification-driven command suite and /mergen-agent lifecycle
  orchestrator are retained as compatibility tooling. External executors own
  planning, implementation, remediation, and progression. Mergen owns independent
  milestone verification.
• Repository presentation, package metadata, charter, principles, citation
  metadata, and pull request intake now use the independent verification boundary.

Verification

• The complete GitHub Actions matrix passed across supported Python versions and
  Windows, together with Ruff, strict mypy, coverage, version consistency, schema
  validation, renderer sync, phantom-completion dogfood, CodeQL, dependency review,
  and gitleaks.