16ed8f1df1
Adds an 8th guardrail and replaces §5.4 with an explicit "if you change X, update Y" mapping covering options, scripts, keybindings, structure, installer, themes, roadmap, conventions, and flake-level changes. Each row names the doc to touch. The closing line forces a one-pass check before declaring a change done — eliminates "docs catch-up" PRs and keeps the distro and its docs from drifting apart.