Data-Driven SEO Content Engine Methodology (How to Operate It, Not "What Google Says")
9-stage closed-loop data content workflow (data → keyword selection → planning → writing → de-AI-ifying → localization → on-page → quality gate → iteration) + 4 hard practical lessons (competitor facts must be verified and dated / compete on "the best stuff is free" not just "free" / deliver complete final drafts instead of diffs / content hits diminishing returns at scale, don't pile pages on new sites that lose index) + off-page authoritative backlink playbook (directories / review outreach / communities / "open-source hosted version" brand leverage) + main skill orchestrating subagents. Fills the missing "how to operate" layer that the gsc-* reference layer lacks.