Astro Guideline: Routing — Use getStaticPaths for SSG. Description: Generate static pages at build time. Do: getStaticPaths for known dynamic routes. Don't: Fetch at runtime for static content. Good Example: export async function getStaticPaths() { return [...] }. Bad Example: No getStaticPaths with dynamic route. Severity: High. Docs: https://docs.astro.build/en/reference/api-reference/#getstaticpaths.