v0.19.0 — context-persistence slices + goal-audit hardening

Added

• Budgeted context-persistence slices — scripts/context-slice.mjs derives per-task
  .codex-flow/CONTEXT-T<n>.md (≤ 4000 tokens) and resume .codex-flow/RESUME.md (≤ 8000 tokens)
  views from PLAN.md and TASKS.md, preserves mandatory task text and statuses, and drops only whole
  lower-priority items with restorable PLAN.md pointers.
• Git-anchored decision read-back — Decision-log blocks record Anchor: SHAs, and derived
  slices stamp them [fresh] or [verify]; missing or invalid anchors and git failures degrade to
  [verify] while full PLAN.md remains authoritative and standalone installs retain a direct-read
  fallback.
• Durable requirements with criterion-level coverage — .codex-flow/REQUIREMENTS.md records
  confirmed criteria verbatim as atomic R<n>.<m> IDs; append-only confirmed Deltas preserve
  mid-run changes and reset affected downstream approvals. scripts/requirements-coverage.mjs
  rejects uncited and unknown IDs at the Phase 3 gate, and final review reports every ID met/not-met
  with evidence.
• Authoritative 10-key run state — .codex-flow/STATE.md replaces file-existence inference with
  the current phase, three approval records, immutable runBaselineRef / known-red / dirty-baseline
  values, checkpoint choice, execution mode, and a separate resumeHead.
• Session lineage and status-aware recovery — TASKS.md gains session metadata plus an append-only
  transition log; resume reconciles orphaned in-progress work. Wave scheduling uses done tasks to
  satisfy dependencies, waits on in-progress tasks, and blocks dependents of failed or unknown
  states.
• Single-writer parallel coordination — one coordinator owns every .codex-flow/* write while
  workers return structured handoffs covering touched files, checks, findings, proposed decision-log
  data, and session IDs.
• Stronger context slices — task slices always include a stamped contracts index, compact the
  known-red baseline, and rank decision blocks by explicit Applies to: scope before recency; the
  execution prompt carries the run-position recitation header.