write-chapter: author chapters single-pass (drop the multi-agent Workflow)

[yagop]

Per request, the write-chapter skill no longer uses the multi-agent Workflow (and is no longer branded "ultracode").

What changed

• Step 4 ("Spawn the Workflow" → "Write the chapter and the samples"): the chapter doc and every sample are now authored directly in the working tree. No Workflow/agent()/pipeline() calls, no args object.
• Appendix A ("the Workflow script" → "how to write and review the files"): the ~110-line orchestration script is replaced by a concise writing guide + the review checklist — the same adversarial checks the old review agent ran (no invented SDK surface, convention violations, bun run failures, placeholders, non-ASCII, golfed code), now run by hand over each file before committing.
• Intro, steps 5/6, and Special cases reworded from "the Workflow returns…/the review agents…" to single-pass language. The Review-flags concept is kept.
• Appendix B conventions are byte-identical (only the heading parenthetical changed, since args.conventions no longer exists).

Net: 241 → 134 lines. As a bonus this removes the escaped-backtick footgun in the old embedded script (the (`:::`) that broke a prior run).

🤖 Generated with Claude Code