paperd v0.2.1

Changes

• Align app and bundled worker release metadata for paperd 0.2.1.
• Update worker packaging/version detection to use the 0.2.1 pyproject version.
• Refresh user-facing setup guidance for the venv + pip worker environment.
• Generate the Homebrew cask without a uv formula dependency.

Verification

• swift test
• worker/.venv/bin/pytest worker/tests
• Developer ID signing, notarization, stapling, and Gatekeeper assessment