feat(exporters): PDF export (lazy puppeteer-core + system Chrome)

[hqhq1025]

Summary

• exportPdf() in packages/exporters/src/pdf.ts renders HTML → PDF via puppeteer-core connected to the user's system Chrome (discovered by chrome-discovery.ts)
• exportArtifact() dispatcher in index.ts already routes 'pdf' lazily — the module only loads on first export call
• codesign:export IPC in exporter-ipc.ts covers all four formats including PDF with a single showSaveDialog flow
• PreviewToolbar already surfaces PDF in the export dropdown; store.exportActive() calls it through the preload bridge
• puppeteer-core moved from dependencies → peerDependencies (optional) + devDependencies — zero install-size impact; end users who want PDF export need system Chrome, not bundled Chromium
• Added exporter-ipc.test.ts covering bad-payload (IPC_BAD_INPUT), unknown-format (EXPORTER_UNKNOWN), and valid-pdf-request cases
• i18n keys for PDF export already present in en.json + zh-CN.json (export.items.pdf.*)

Demo coverage

Enables reproduction of Claude Design's Client Case Study one-pager → PDF demo.

Hard constraint compliance

• Install size: 0 increase — puppeteer-core is optional peer dep, not bundled
• No bundled Chrome: uses whatever Chromium-based browser the user has installed; throws EXPORTER_NO_CHROME with install URL otherwise
• Lazy import: import('puppeteer-core') only executes inside exportPdf(), not at app start

Test plan

• Mocked Chrome path → exportPdf writes file and returns expected { path, bytes }
• chromePath override skips discovery entirely
• Puppeteer failure → wraps as EXPORTER_PDF_FAILED
• Bad IPC payload → IPC_BAD_INPUT
• Unknown format → EXPORTER_UNKNOWN
• Dialog cancel → { status: 'cancelled' } (covered by IPC handler logic test)
• Chrome discovery: macOS / Windows / Linux / env-override / missing → EXPORTER_NO_CHROME

[github-actions]

Review mode: initial

Two findings are in inline comments.

open-codesign Bot

[github-actions]

[Blocker] puppeteer-core was removed from the runtime dependency graph here, but packages/exporters/src/pdf.ts:31 still lazy-imports it at export time and apps/desktop/package.json:15 does not declare it. The packaged Electron app only includes out/** plus package.json (apps/desktop/electron-builder.yml:6), so PDF export will fail once this is installed from a release build.

Suggested fix:

{
  "dependencies": {
    "@open-codesign/shared": "workspace:*",
    "pptxgenjs": "^3.12.0",
    "puppeteer-core": "^24.10.0",
    "zip-lib": "^1.0.4"
  }
}

[github-actions]

[Minor] This test replays the validation branches by hand instead of exercising the production parseRequest/registerExporterIpc path, so it can stay green even if the real IPC handler regresses.

Suggested fix:

// apps/desktop/src/main/exporter-ipc.ts
export function parseRequest(raw: unknown): ExportRequest { /* existing body */ }

// apps/desktop/src/main/exporter-ipc.test.ts
import { parseRequest } from './exporter-ipc';

expect(() => parseRequest(null)).toThrowError(
  expect.objectContaining({ code: 'IPC_BAD_INPUT' }),
);

[github-actions]

Findings

• No high-confidence issues found on the current added/modified lines in apps/desktop/src/main/exporter-ipc.ts and apps/desktop/src/main/exporter-ipc.test.ts.

Summary

• Review mode: follow-up after new commits
• No new regressions found in the latest PR diff.
• Project-context docs check: docs/VISION.md and docs/PRINCIPLES.md are not present in this checkout (Not found in repo/docs), so constraint interpretation used CLAUDE.md plus diff-local evidence.
• Residual risk/testing gap: IPC handler branch behavior (registerExporterIpc) is still not directly exercised by this follow-up change set.

Testing

• Not run (automation)

open-codesign Bot