feat: decide the order games are listed in

Nothing did. Every surface that lists a game rendered App's `games`, which is
the order lanes first appear in the feed — whichever game happened to hold the
first event row. It is arbitrary, it moves as events come and go, and it was
the same complaint the first-run picker had.

So `orderGames` is one rule in one place, and `prefs.gameOrder` is where the
reader's own answer goes. Absent means they have never placed a game rather
than an empty order, which is the distinction `knownGames` already draws and
the same trap: every install predating the field is in that state, and reading
it the other way would hand them a blank list. They get A–Z by the name on
screen instead.

Two properties carry the weight, and both are tested rather than asserted. The
result is always a permutation of the lanes given, because a game dropped
here looks exactly like a game switched off and switching it on would not
bring it back. And a lane the order does not name trails the ones it does, so
a game we add later never lands in the middle of a hand-made order and a
retired source keeps its slot for when it returns.

Nothing reads it yet.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/client/state/usePrefs.ts

@@ -47,6 +47,28 @@ export interface Prefs {
    * them in.
    */
   knownGames?: LaneId[];
+  /**
+   * The order the reader put their games in.
+   *
+   * Absent means they have never placed one — not that they have no order, and
+   * not an empty order. Every install predating this is in that state, so the
+   * fallback has to be a rule rather than a stored value: `orderGames` sorts
+   * alphabetically by name, which is what the first-run picker already does.
+   * A game added later trails everything they placed by hand.
+   *
+   * `| undefined` is explicit because `exactOptionalPropertyTypes` is on and
+   * "Reset to A–Z" is a patch that writes the field away — `{ gameOrder:
+   * undefined }` has to be assignable for the reset to typecheck, and
+   * `JSON.stringify` drops it on the way to storage.
+   *
+   * Not a key space and not a migration: one more field in the single `prefs`
+   * blob, like `timelineGroup`. It rides the export for free, though note that
+   * `importProgress` restores progress, dailies, ignores and the reader's own
+   * games — never prefs — so an imported file does not bring an order back.
+   * That asymmetry predates this field and applies to region, theme and view
+   * alike.
+   */
+  gameOrder?: LaneId[] | undefined;
   /**
    * One game to look at right now, or null for all of them.
    *