Let a parser report that a page states it lists no events

A count of zero has two causes and nothing downstream can tell them apart:
a source whose selectors all broke, and a game that is simply between
patches. Both parse to nothing, so `canParse` plus a row count cannot
separate them — and the pipeline currently has to assume the worst, which
is right for a redesign and wrong for a quiet week.

`statesNoEvents` is the seam for the one thing that can settle it: the
page's own words. Optional, because most pages say nothing either way, and
absent means the strict gate stands.

No parser implements it yet and nothing reads it — the contract widens here
so the parser and the refresh gate can land as their own changes.

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

src/ingest/adapters/index.ts

@@ -227,6 +227,9 @@ function toAdapter(spec: SourceSpec): Adapter {
     parserId: spec.parserId,
     minIntervalMs: spec.minIntervalMs ?? SIX_HOURS_MS,
     priority: spec.priority ?? 0,
+    statesNoEvents(html: string): boolean {
+      return parser.statesNoEvents?.(html) ?? false;
+    },
     parse(html: string, ctx: ParseContext): GachaEvent[] {
       // A site redesign should fail the run loudly rather than publish an empty
       // calendar, which would read as "no events" to a user.

src/ingest/adapters/types.ts

@@ -33,6 +33,14 @@ export interface Adapter {
   priority: number;
 
   parse(html: string, ctx: ParseContext): GachaEvent[];
+
+  /**
+   * True when the page itself states that it currently lists no events, so an
+   * empty parse is this source's real answer rather than a source that broke.
+   * Absent unless the underlying parser implements it — see
+   * `SourceParser.statesNoEvents`.
+   */
+  statesNoEvents?(html: string): boolean;
 }
 
 export const SIX_HOURS_MS = 6 * 60 * 60 * 1000;

src/ingest/parsers/types.ts

@@ -26,5 +26,19 @@ export interface SourceParser {
    */
   canParse(html: string): boolean;
 
+  /**
+   * True when the document is one this parser understands *and* the document
+   * itself says it currently lists no events.
+   *
+   * Optional, and absent for every parser whose pages do not say so. It exists
+   * because `canParse` and a row count cannot together tell a source that broke
+   * from a game that is simply between versions: both yield nothing. A page
+   * that states its own emptiness can, and the refresh runner stores that as a
+   * real answer instead of counting it as a failure — see
+   * `scripts/refresh-sources.ts` § the parse gate. Anything less explicit than
+   * the page's own words belongs on the strict side of that gate.
+   */
+  statesNoEvents?(html: string): boolean;
+
   parse(html: string, ctx: ParseContext): GachaEvent[];
 }