v0.12.28: @newsroom.writer: how to write here

A guide beside the article sources, admin/content/articles/README.md, for whoever writes the next article: the voice as it is counted from the nine articles written here, the seven wording rules and the three the desk keeps, the shape part by part with the anchors the build reads, how a figure is declared and drawn, the graph beside the article, what to read before writing, the run from the markdown to a release, and a checklist. Card 050. publish.py already skipped a README in that folder, so the guide never reaches the generator's tree.