The overview rendered four anonymous module tiles and half a page of empty
space, which undersold 63 existing lessons. It now stacks four module
sections that list every lesson as a chip with status and variant dots, and
the header states the real scope: 4 modules, 63 lessons, 262 variations.
Mastery moves from a flat two-variation counter to per-module thresholds
(3/4/4/5) backed by persisted variant signatures — a hash over each roll's
expected answers. That triples the practice runs to full mastery without
authoring a single new lesson, and fixes a dedup hole where the same
variation counted twice after a page reload.
Existing progress is preserved: `done` is sticky, so raising the bar never
revokes a check mark someone already earned.
Also fixes `yarn test`, which passed quoted globs Node 20 does not expand —
it exited 0 without running a single test.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
