docs: the focus bar's games are the reader's order, not the feed's

Left over from before `orderGames` existed. The prop says feed order and App has
been handing it `enabled`, which is the reader's order filtered — so the comment
described the one thing that stopped being true when every game-listing surface
started going through the same rule.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

src/client/components/GameFocus.tsx

@@ -23,7 +23,12 @@ export function GameFocus({
   onFocus,
   onAdvance,
 }: {
-  /** Games the reader has switched on, in feed order. */
+  /**
+   * Games the reader has switched on, in **their** order.
+   *
+   * Was feed order — whichever game held the first event row — until
+   * `orderGames` became the one rule every surface listing a game goes through.
+   */
   games: LaneId[];
   focus: LaneId | null;
   /** Outstanding rows per game, so a chip says whether it is worth a visit. */