feat: add Chaos Zero Nightmare, which the game8 parser already reads

No parser work at all — a GameId, a games entry, a SOURCES line, a fixture and
a test. The page lists six current events and the parser publishes four; the
two it skips print "Start Date: -", and no start means no event ID, so that is
the skip-never-guess rule working rather than a silent drop.

The cost is worth stating plainly: this is the ninth game8 source, and game8's
edge answers the Actions runner with a 202 and a bot-management body, so the
lane is built from a checked-in fixture in CI from day one and only a manual
`bun run refresh` moves it. freshness() discloses that in the footer, which is
what it is for.

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

docs/PRD.md

@@ -59,7 +59,7 @@ have a source — this table is the launch scope, not a roster to keep in sync.
 
 Adding a game must require no change to `GachaEvent` — only a `GameId` entry, its `games.ts`
 metadata, and a source registration. That is the test of whether the data model is right, and it has
-held: the fifteen games here have cost the event schema nothing. Per-game *metadata* does occasionally
+held: the sixteen games here have cost the event schema nothing. Per-game *metadata* does occasionally
 grow (Reverse: 1999 needed `resetHourLocal` for a 05:00 reset), which is a different file and moves
 no stored key. A game may have several sources; see `docs/INGESTION.md` § Three layers.
 
@@ -90,7 +90,7 @@ default `"game"` — the board every existing reader already has). Merged, the o
 `endingSoonestFirst`, the same comparator behind the list's "Ending soonest" (F2), so the two views
 cannot mean different things by the same words and an unannounced end still sorts behind every dated
 one rather than claiming a place in the queue. Merged there is also no lane heading to say whose
-event a bar is, and hue alone cannot answer that once fifteen games share a stack — so each bar
+event a bar is, and hue alone cannot answer that once sixteen games share a stack — so each bar
 carries its game's short name, with the full name in its tooltip. A bar too narrow for a tag and a
 title both keeps the title: a chopped game name reads as a broken word, and the hue and the tooltip
 still answer it.