feat: add Game8 parser with Genshin and NTE adapters

Parsers are keyed by site template, not game: one Game8 parser serves
every Game8 page, and adapters bind a URL and game to a parser. Adding a
source for a known site is one SOURCES entry.

Game8 uses at least three templates. This handles label/value detail
tables (Genshin, 9 events) and column tables (NTE, 13 events). Its
image-grid schedule has no year and no end date, so Arknights: Endfield
is not supportable from that source and gets no adapter.

canParse is a structural tripwire: a site redesign fails the run loudly
instead of publishing an empty calendar that reads as "no events".

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

src/ingest/parsers/index.ts

@@ -0,0 +1,16 @@
+import { game8Parser } from "./game8.ts";
+import type { SourceParser } from "./types.ts";
+
+/**
+ * Every known site template. Adding a source for a site already listed here is
+ * an entry in `adapters/index.ts`; adding a new *site* means a parser module
+ * here and one line below.
+ */
+export const PARSERS: SourceParser[] = [game8Parser];
+
+export function parserById(id: string): SourceParser | undefined {
+  return PARSERS.find((p) => p.id === id);
+}
+
+export type { SourceParser } from "./types.ts";
+export { game8Parser } from "./game8.ts";