KDS docs mobile responsiveness

mandatory

Audit + ongoing contract that every page on `kds.koder.dev` is usable on mobile screens (Compact width < 600 dp). Material parity (`/develop` cross-cutting concern). Distinct from `specs/web-apps/responsiveness.kmd` (which covers Koder web apps); this spec covers the docs site itself.

Spec — KDS docs mobile responsiveness

Facet *evelop*of Koder Design. Material parity: https://m3.material.io/develop (cross-cutting concern).

Scope

Every public page under `https:/ds.koder.dev/{locale}