Removes both vi.mock('pdfjs-dist', factory) and
vi.mock('pdfjs-dist/build/pdf.worker.min.mjs?url', factory) from
PdfViewer.svelte.spec.ts — the ManualMockedModule registrations that were
racing with vitest-browser-playwright's birpc teardown channel.
PdfViewer.svelte now accepts an optional libLoader prop (typed as
Parameters<typeof createPdfRenderer>[0]) that is passed untracked to
createPdfRenderer(). Tests supply a vi.fn() fake loader directly as a prop;
production code uses the default loader that imports the real pdfjs-dist.
The birpc route handler for pdfjs-dist is never registered, so no teardown
race is possible. Fixes#535.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>