docs: /reference/pdf/を翻訳

[3w36zj6]

close #360

[Copilot]

Pull request overview

/docs/reference/pdf/（PDFエクスポート／PDF規格に関するリファレンスページ）を日本語化し、翻訳ステータスを更新するPRです（Issue #360 対応）。

Changes:

• PDFエクスポートのリファレンス本文（PDF versions / PDF/UA / PDF/A など）を翻訳
• 追加オプション（--no-pdf-tags）など、未翻訳だった箇所を日本語化
• website/translation-status.json で /docs/reference/pdf/ を translated に更新

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
website/translation-status.json	/docs/reference/pdf/ を translated に更新
docs/reference/export/pdf.md	/docs/reference/pdf/ に対応するPDFカテゴリページ本文を翻訳

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.