UX: per-module quizzes

Part of the UX backlog. Raised on 2026-06-11.

Per-module quizzes, so a reader can check they absorbed a module rather than only having clicked through it.

Scope

• A question format in the content files or the manifest — needs designing. Markdown is the current source of truth for prose, so quiz data probably belongs in course-manifest.json or a sibling file rather than inline in the prose, to keep ##-based section splitting intact (see README).
• Rendering at the end of a module in ModulePlayerClient.
• Answers checked client-side. No server, no accounts (see the auth note in the README).

Watch out

lib/progress.ts currently tracks completedSections and a completed flag per module. If quiz results should be remembered, the ProgressStore shape in lib/types.ts changes, and existing readers have older data in localStorage — so reads need to tolerate the old shape.

Out of scope

Grading, certificates, or anything that reports results anywhere.

Done when

At least one module has a working quiz, and progress still loads for someone who used the site before the change.

Read the README, then inspect ModulePlayerClient, course-manifest.json, lib/progress.ts, and lib/types.ts. Decide where quiz data belongs and how a module renders and checks answers client-side, while preserving loading of older localStorage data. Done means one module has a working quiz and existing progress still loads.