v1.3.0

What's Changed

• Improve PDF paragraph extraction for two-column and block-based layouts.
• Reduce incorrect line-by-line translation on ragged or left-aligned PDF text.
• Add macOS/Linux setup script and installation docs.
• Bump extension manifest version to 1.3.0.

Merged PR: #1 from hackerpeanutjohn/feat/pdf-columns-paragraphs-macos