archfit v1.2.0

archfit v1.2.0

This release adds deterministic coupling gating, book-aligned coupling
classification updates, warm fact-cache reuse, and off-gate LLM review
workflows.

Breaking metric change: ScoreVersion is now bc_score.v4. v4 scores are NOT
comparable to bc_score.v3 scores — treat the first v4 run as a new
measurement, and re-baseline (archfit baseline) before relying on
coupling.gate.max_drop. score_version now appears at the top level of
--json output so consumers can key on it.

• New coupling.gate controls let CI fail on a minimum coupling band and/or a
  maximum score drop, separate from rule violations; verdict reporting now
  keeps per-metric gate reasons explicit.
• Three classification changes keep the book formula intact while fixing the
  inputs: const/var reads score Model (not Functional), pure-data Go DTOs can
  reach Contract across declared public boundaries, and declared
  external_systems enter scoring at D=10.
• Warm runs now reuse unchanged extractor subprocess facts via the
  content-addressed fact cache; use --no-cache for a cold control run.
• archfit config enrich labels and config enrich abstained draft review-only
  LLM labels for weak or abstained edges, and config update --llm proposes
  review material for subdomains, roles, and volatility. Approved labels stay
  deterministic YAML; stale evidence is ignored; LLM output never decides the
  gate.