Expand markdown editor guidance

[rrih]

Summary

• adds destination-specific guidance for README, blog/static-site, and team-note Markdown workflows
• adds an FAQ for choosing a practical online Markdown editor workflow
• keeps ad density, editor logic, AdSense settings, and external domains unchanged

Selected action

• Type: existing-page-expansion
• Target: https://rrih.github.io/tools/markdown-editor/
• Automation mode: auto-pr
• Control issue: Refs Revenue accelerator control tower #15

Expected KPI impact

• Improves relevance for markdown editor, online Markdown editor, README Markdown, blog Markdown, and team-note drafting intents.
• Adds supporting copy and FAQ depth without adding thin pages or extra ad units.

Data rationale

• data/growth/accelerator/latest.json listed Markdown Editor expansion as an auto-pr action after 15 impressions and 0 clicks in the latest GSC window.
• Existing draft PRs Improve animation generator CTR copy #26 and Add overtime pay calculator #28 were both CLEAN, CI success, and waiting for human review, so this low-risk unrelated auto-pr stayed within the 3 open PR cap.

Verification

• bash /Users/rrih/.codex/skills/rrih-github-io-revenue-accelerator/scripts/github_preflight.sh rrih/rrih.github.io
• bun test
• bun --bun tsc --noEmit
• bun run lint (pass with existing 9 warnings)
• bun run build
• bun run dev-check
• Browser check on /tools/markdown-editor/: new heading and FAQ visible at 1280px and 390px, no horizontal overflow, no console errors