v1.4.2 — persistent cross-stage state file

Added

• Persistent cross-stage state file — .article-craft-state.json, co-located with each article. The orchestrator writes stage status (running / completed / failed / skipped) with per-stage result payloads at every pipeline boundary. Resurrects scripts/pipeline_state.py (deleted in v1.3.4) with a real CLI, proper schema versioning, atomic writes, and now actually wired into the orchestrator.
• pipeline_state.py CLI with subcommands: init, start, complete, fail, skip, show, missing-stages, cleanup, reset, artifact. The missing-stages command is the primary --upgrade entry point — it returns structured JSON with missing / done / stale / skipped lists plus a source field (state_file / hybrid / heuristic).
• State-file conflict resolution: article content remains ground truth. If state says images: completed but the body still has <!-- IMAGE: --> placeholders, the stage is flagged stale and re-runs. source: "hybrid" in the output makes the disagreement visible.

Changed

• --upgrade mode now reads .article-craft-state.json first and falls back to content heuristics only when the file is absent. Articles predating v1.4.2 still work through the heuristic path (pure source: "heuristic" result).
• orchestrator/SKILL.md Step 2 now initializes the state file after write produces an article path. A new "State Write Protocol" section documents start/complete/fail/skip calls + per-stage result payload shapes for all 9 stages.
• publish stage cleanup: in standard mode, the state file is deleted after publish completes successfully — the pipeline is done, no state needed. draft and quick modes preserve the state file so future --upgrade can resume from it.

Design notes

• State file lives next to article.md so it survives git mv. Schema is versioned (schema_version: "1") for future migrations; the current pipeline_version is recorded for audit.
• Standalone skill invocations (/article-craft:lint, /article-craft:review) do not write state. State is orchestrator-only, since it only has meaning for multi-stage pipeline runs.
• Closes the "No persistent cross-stage state file" item in CLAUDE.md's "Known design debt" list. 3 items remain: verify rename/split (source-vet + verify-claims), images batch 429 backoff, and review Phase 2 auto-modify → scoring-only.