Only warn about staleness for games the reader has switched on

The footer's staleness notice is an instruction, and the only remedy it
offers is "go and check that game's source page". That is not something a
reader can act on for a game they turned off and cannot see a single row
of — and with nineteen lanes, naming eleven they do not play buries the one
they do. A new lane arrives switched off (F8), so an untouched install was
being warned about most of the catalogue.

Scoped in two places, not one: the named list, and the count the
summarising branch measures against. Without the second, that branch would
never fire for a reader with most of the calendar off and they would get a
list where a sentence was the readable answer.

The notice now also states whose games it counted, in the words NextUp
already uses for the same set. Narrowing what the footer measured while
still printing "nothing has refreshed" would turn a claim about four games
into one about eighteen, in the one paragraph on the page whose job is
being trusted about age.

The headline age and the credits stay whole: the first is a fact about the
feed and feeds the bug form, the second is attribution owed to every source
we read regardless of what is on screen.

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

docs/PRD.md

@@ -447,6 +447,21 @@ The footer shows when the feed was last updated, per game. If a game's data is m
 stale, its lane carries a warning badge. Never present stale data as current — the whole value
 proposition is trust in the dates.
 
+**The staleness notice names only the games the reader has switched on, and says that it does.**
+The headline age is about the feed and stays whole; the notice under it is an *instruction*, and the
+only remedy it offers is "go and check that game's source page" — which a reader cannot act on for a
+game they turned off and cannot see a single row of. With nineteen lanes and two switched on, naming
+eleven they do not play buries the one they do, and a warning about games nobody reads is a warning
+nobody reads (F8: a game we add is a game they never asked for, and arrives switched off, so an
+untouched install would be warned about the whole catalogue).
+
+Both halves of that are load-bearing. Scoping it silently would be the worse half: "nothing has
+refreshed" is a claim about the whole calendar, so a reader with fourteen of eighteen lanes off would
+read a sentence about four as one about all of them. The notice therefore states whose games it
+counted, in the same words the empty list uses — *the games you have switched on*. Credit in the
+column beside it is owed to every source we read and is not scoped; nor is the "last refreshed" line,
+which reports the feed and feeds the bug form.
+
 **F15 — Light mode, with dark still the default.**
 The app is a lit instrument panel and that is what it should be on first sight, but it is also read
 on a train in daylight and by people who find a dark UI harder rather than moodier. A public fork