Release 0.2.1

[rudrankriyam]

What changed

• Excludes the DocC catalog from normal SwiftPM target discovery, removing the unhandled-file warning.
• Passes the catalog path explicitly in documentation commands so all three hand-written articles stay in the archive.
• Updates the package examples and changelog for 0.2.1.

Why

Xcode 27 beta 3 reports Documentation.docc as an unhandled target file during swift test. Excluding it alone makes DocC silently omit Getting Started, Analysis Results, and Streaming Audio, so the documentation commands now supply the catalog path themselves.

Validation

• Scripts/validate-repository.sh
• swift test (8 tests)
• Generic iOS 27 build
• DocC archive generation with all three articles present
• No unhandled-file warning in any release check
• git diff --check

Validated with Xcode 27 beta 3 (27A5218g) on macOS 27.0 (26A5378j).