Write a guide against the concept graph

This repo has two kinds of content that must agree:

• Concepts (plugins/runpod/skills/runpod-usage/concepts/*.yaml) hold exact facts as rules, each citing a public source. They are the source of truth for what is true.
• Guides (every SKILL.md, reference/*.md and golden path) explain, teach and demonstrate. They are the source of truth for how to do it.

A guide states facts that the concept rules support, and links to the concepts it covers. A concept is covered by at least one guide. pnpm check:guides enforces both links.

Writing or changing a guide

1. Find the concepts it touches before writing (run these in ontology/tools/):