Function implementers

__tests__/adaptive-explore-sizing.test.ts:273–274

(id: string)

    expect(formatter).toBeTruthy();

    const implementers = (id: string) =>
      cg.getIncomingEdges(id).filter((e) => e.kind === 'implements' || e.kind === 'extends').length;

    // The whole gate hinges on this signal — assert the fixture actually
    // produces the >=3 / <3 split, so a TS-extraction change fails here loudly