v8.4.0

• Add optional acceptance-criterion IDs. A criterion may be written - AC-01 (REQ-01): ... with
  one parent requirement; tasks, prompts, and EV-* records cite it in the existing Requirement anchors field, and an AC-* anchor implies its parent requirement. Optional Examples: use
  Given/When/Then only as notation. Features without AC-* behave exactly as in 8.3.0.
• Show per-criterion coverage in doctor --evidence-graph (text, --json acceptance_criteria,
  and --html) when a feature uses AC-*. New broken edges, each exiting 1: duplicate-ac-id,
  ac-unknown-requirement, unknown-ac-anchor, and no-ac-evidence. A line that resembles a
  criterion but does not match is reported as malformed AC line and never counts as coverage.
• Clarify contracts (no new Status value, EV-* field, contract kind, or dependency): sensor
  change classes infrastructure repair, automation repair, contract correction, and
  contract weakening in evidence-standard.md; a mock of the seam under test is a shallow
  sensor; check and review flag orphan behavior; a recorded RED states its cause
  (missing-behavior, test-defect, environment, unrelated-failure); acceptance discovery
  separates blocker from assumption, confirms prose before examples, and asks for a
  forbidden-outcome example on security, permission, or data criteria. Skills only cite these
  rules. The tdd baseline version is unchanged.
• Fix a gap in the 1.15.0 note: no script protected the stable false-positive class names. The
  contract check now fails when any of the ten false-positive classes or four sensor change
  classes leaves its reference section.
• Add nine behavior cases to the corpus and a seventh Level A fixture family, acceptance contract
  (F7), whose oracle compares a test's assertion lines so setup repair passes and an edited
  expectation is critical. No real-host campaign ran, so no behavior improvement or cost claim is
  made.
• Add docs/acceptance-driven-development.md and its pt-BR counterpart, and update the idea-to-spec
  golden to AC-* IDs while task-management stays REQ-only.