feat(nikki): track Infinity Nikki

Adds the game and its Game8 events page. One `SOURCES` entry against the
existing game8 parser, plus one date shape that page needs:
`parseLabelledStartEnd` reads a duration cell holding `Start: <date>` and
`End: <date>` split by a `<br>`, which a tag-stripping reader flattens
into one run of text.

Four of the seven events say `End: Permanent`. That is the source telling
us there is no deadline, so they publish with `endsAt: null` and
`endPrecision: "unknown"` rather than a plausible date. The labelled cell
is also structure end to end, so it never becomes a summary — stripping
the leading half would leave "End: Permanent" standing where a
description belongs.

Verified by re-extracting the page with a throwaway script independent of
the parser: 7 rows in, 7 events out, every date matching.

Note the source itself is stale — its "Current Events" table still lists
January-May 2025 and "Upcoming Events" says there are none. The adapter is
right; the page looks abandoned, and Nikki coverage worth relying on needs
a second source at a higher priority.

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

src/shared/games.ts

@@ -53,6 +53,7 @@ export const GAMES: Record<GameId, GameMeta> = {
   // and `america` already resolves to -5, so Europe is the only real override.
   endfield: { id: "endfield", name: "Arknights: Endfield", short: "Endfield", hue: "#E8635A" , studio: "Hypergryph", dailyTasks: "Daily missions", resetOffsets: { europe: -5 } },
   nte: { id: "nte", name: "Neverness to Everness", short: "NTE", hue: "#C77DFF" , studio: "Hotta Studio", dailyTasks: "Daily tasks" },
+  nikki: { id: "nikki", name: "Infinity Nikki", short: "Nikki", hue: "#F27BB0" , studio: "Infold Games", dailyTasks: "Daily tasks, Vital Energy" },
 };
 
 export const GAME_LIST: GameMeta[] = Object.values(GAMES);