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]>

test/adapters/game8.test.ts

@@ -27,6 +27,7 @@ const CASES: Array<{ adapter: Adapter; fixture: string }> = [
   { adapter: adapter("zzz-game8-events"), fixture: "fixtures/zzz/game8-events-2026-08-14" },
   { adapter: adapter("endfield-game8-events"), fixture: "fixtures/endfield/game8-events-2026-08-14" },
   { adapter: adapter("endfield-wikigg-events"), fixture: "fixtures/endfield/wikigg-events-2026-08-14" },
+  { adapter: adapter("nikki-game8-events"), fixture: "fixtures/nikki/game8-events-2026-08-17" },
 ];
 
 async function runAdapter(adapter: Adapter, fixture: string) {
@@ -226,6 +227,37 @@ describe("endfield", () => {
   });
 });
 
+describe("nikki", () => {
+  const fixture = "fixtures/nikki/game8-events-2026-08-17";
+
+  test("reads a labelled Start/End cell, and takes no end from 'Permanent'", async () => {
+    // The duration cell is "Start: January 24, 2025 End: Permanent" — two
+    // labelled halves separated by a <br>, which a tag-stripping reader sees as
+    // one run of text.
+    const events = await runAdapter(adapter("nikki-game8-events"), fixture);
+    expect(events).toHaveLength(7); // every row of the current-events table
+
+    const fiesta = events.find((e) => e.title === "Fireworks Fiesta");
+    expect(fiesta?.startsAt).toBe("2025-01-24T00:00:00.000Z");
+    // "Permanent" is not a date and does not become one.
+    expect(fiesta?.endsAt).toBeNull();
+    expect(fiesta?.endPrecision).toBe("unknown");
+
+    const bubble = events.find((e) => e.title === "Bubble Season");
+    expect(bubble?.startsAt).toBe("2025-04-28T00:00:00.000Z");
+    expect(bubble?.endsAt).toBe("2025-06-12T00:00:00.000Z");
+  });
+
+  test("never presents the labelled cell's own text as a summary", async () => {
+    // "End: Permanent" is structure, not a blurb. Leaving it in the summary
+    // slot would show a reader a date the parser deliberately refused to use.
+    const events = await runAdapter(adapter("nikki-game8-events"), fixture);
+    for (const e of events) {
+      expect(e.summary).toBeNull();
+    }
+  });
+});
+
 describe("wiki.gg parser", () => {
   test("reads exact per-region timers", async () => {
     // The first source that states region-scoped ends. Asia and the Americas