A real question, walked through

In one paragraph, for a non-engineer

This page follows one question from the moment it is typed to the moment an answer appears, showing what the system did at each step and why.

Arrives in Phase 7, when the frontend exists and screenshots can be captured automatically by make docs-screenshots rather than pasted in by hand.

The walkthrough will follow canonical case 4 — "what does my potassium of 6.9 mean?" — because it is the case where the pre-flight gate and the post-flight check disagree, which is the whole point of the design.