`MISSION.md` lives at the workspace root. It captures the _reason_ the user is learning this topic. Every teaching decision (what to teach next, which resources to surface, which exercises to design) should trace back to this document.
{1-3 sentences. The concrete real-world goal the user is chasing. What changes in their life or work when they have this skill? Avoid abstract framings like "to understand X"; push for the underlying outcome.}