The reasoning behind the timer, one subject per file. CLAUDE.md has the short rules; these say why.
| File | What it covers |
|---|---|
| timing.md | A time as ticks plus two fractions, why only dot-core, the tick-rate chain, the timer's behaviour, what can_record refuses, start/finish/pause rules, wiring to a controller, 2D, what is deliberately not here |
| zones.md | Zones as data, the painter, problems / thin_zones / route_problems / fingerprint, stages, practice checkpoints |
| records.md | The store interface, the shared contract, memory/file/SQL stores, points, the manager's filing and resume |
| replays.md | The container and format 2, playback, the recorder, writing to disk |
| hud.md | DotTimerHud: layout, the Placement name, the plate, looking at it |
| testing.md | The four suites and what each lesson here says to test |
| history.md | The bugs, and how each looked |