The rules a future change could undo without noticing, written where whoever
touches that area next will read them.
Three of them are traps rather than descriptions. An absent `gameOrder` means
the reader has never placed a game, not an empty order — reading it the other
way hands every existing install a blank list, which is the `knownGames`
mistake again. `games` is left in feed order deliberately, because the code
that hides a reader's games diffs it. And the catch-up window bounds display
and never storage: a fortnight's streak exists on one device and nowhere else,
so nothing prunes the log against a window.
The spec that produced the work goes in alongside, including the helper it
specified and the implementation dropped, so the next reader sees why rather
than wondering.
Also corrects the test count in AGENTS.md, which said 772 and was already
stale before this.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
