Add X (Twitter) Articles domain skill

[changtimwu]

Adds domain-skills/x/articles.md documenting how to publish long-form X Articles by driving the editor through the harness.

Why

There is no public API for X Articles (the v2 API only posts a plain long-form post, not the formatted Article object), so the editor has to be browser-driven. The mechanics are non-obvious and cost several exploration steps to work out.

What it captures

• URLs: /compose/articles (list), /compose/articles/edit/<id> (editor), /preview suffix, and the /<handle>/status/<id> the post redirects to after publishing.
• Editor structure: it's Draft.js ([data-testid="composer"]); the longform-* block-type class table; title is a separate textarea.
• The key mechanic: inject content via a synthetic paste ClipboardEvent carrying text/html — Draft.js converts HTML → block types far more reliably than per-line toolbar clicking. Includes the verified HTML→Draft mapping.
• Markdown conversion rules for the editor's limits: no tables (→ bold-led bullet list), no code blocks (→ blockquote / plain), inline code → bold.
• Publish flow: the audience/reply dialog (scope selector to [role="dialog"] — two Publish buttons on screen) and dismissing the paid "Boost" promo.
• Traps: regular Premium is enough; Cmd+A won't clear the editor (delete the draft instead); retina DPR=2 means read coords from getBoundingClientRect, not screenshots.

No run narration, pixel coordinates, or secrets — just the durable site map.

🤖 Generated with Claude Code

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Summary by cubic

Adds domain-skills/x/articles.md that documents how to publish long-form X (Twitter) Articles by driving the Draft.js editor in the browser. It covers access, reliable HTML injection, markdown conversion limits, the publish flow, and UI pitfalls.

• New Features
  • Maps key URLs: /compose/articles, /compose/articles/edit/<id>, /compose/articles/edit/<id>/preview, and final /<handle>/status/<id>; notes regular Premium access and login redirects.
  • Details the editor: Draft.js selectors, longform-* block classes, separate title textarea, and toolbar limits (no tables/code blocks).
  • Describes the robust content path: focus composer, inject text/html via synthetic paste, and the verified HTML→Draft mapping; markdown rules (inline code → bold, code blocks → blockquote, tables → bullets; H1 goes to title).
  • Covers publish flow and traps: two Publish buttons scoped to [role="dialog"], Boost promo dismissal, reliable button targeting via visible text + getBoundingClientRect (DPR-safe), delete-to-reset drafts, and cleaning throwaway drafts.

^{Written for commit 04d1318. Summary will update on new commits.}

[cubic-dev-ai]

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