fix(exporters): paginate sectionless PPTX screenshots

[Sun-sunshine06]

Summary

• preserve existing section-based PPTX screenshot export
• recognize common fallback slide containers (data-slide, data-pptx-slide, data-slide-container, .slide) when no <section> exists
• allow callers to override the fallback slide selector
• paginate sectionless artifacts into viewport-sized screenshots instead of compressing a full-page screenshot into one slide
• add focused PPTX exporter coverage for fallback selectors, custom selectors, multi-page pagination, short pages, and empty artifacts

Closes #284

Validation

• pnpm --filter @open-codesign/exporters test
• pnpm typecheck
• pnpm exec biome check packages/exporters/src/pptx.ts packages/exporters/src/pptx.test.ts .changeset/polite-pptx-pages.md

[github-actions]

Review mode: initial

Findings

• [Minor] normalizePageCount returns Math.max(1, Math.floor(pageCount)) after already Math.ceil in evaluate — the pageCount inside the evaluate function is already an integer via Math.ceil, so Math.floor does nothing; this is harmless but unnecessary. Consider using Math.round or keeping the pageCount as-is from evaluate.
  Suggested fix:

  return typeof pageCount === 'number' && Number.isFinite(pageCount) ? Math.max(1, pageCount) : 1;

• [Nit] Extract PRIMARY_SLIDE_SELECTOR and DEFAULT_FALLBACK_SLIDE_SELECTOR as typed const strings is good, but PRIMARY_SLIDE_SELECTOR is only used once; could be inlined. Not a real issue.

• [Nit] Test mockPaginationPageCount overrides evaluateMock globally, which might affect other tests that rely on evaluateMock returning undefined for non-function calls — but beforeEach resets mocks, and the existing tests do not test the pagination path, so no risk.

Linked Issue Validation

Closes #284. Fetched issue #284 title: "PPTX export produces a single slide when artifact has no <section> elements" with acceptance criteria:

• Fallback to common slide-like containers when no <section> exists
• Paginate viewport-sized screenshots for sectionless artifacts
• Allow caller override of fallback selector

The PR satisfies all acceptance criteria: (1) adds fallback selectors [data-slide], [data-pptx-slide], [data-slide-container], .slide; (2) paginates by viewport height; (3) exposes slideSelector option. 5 new focused tests cover fallback, custom selector, multi-page, short page, and empty artifact. The claim to close #284 is correct.

Summary

Well-structured, well-tested PR. The diff is clean and follows project conventions (lazy-loading of puppeteer, no silent fallback, proper error handling, changeset added). The only minor observation is the redundant Math.floor in normalizePageCount. Merge-ready after optional cleanup.

Open-CoDesign Bot

[github-actions]

Review mode: follow-up after new commits

Findings

No new issues. The previous [Minor] finding about redundant Math.floor in normalizePageCount has been resolved — the function now uses Math.max(1, pageCount) directly, matching the suggested fix from the previous review.

Linked Issue Validation

PR title/body claims Closes #284. The diff satisfies all acceptance criteria (fallback slide selectors, pagination, custom selector override, tests). The claim is correct.

Summary

All prior findings addressed. The code is clean, well-tested, follows project conventions (lazy imports, changeset added, no silent fallbacks, proper error handling). Ready to merge.

Open-CoDesign Bot