v1.6.0 - Native Swift Rewrite (Preview)

What's new

Introduces a native macOS Swift/SwiftUI rewrite of the Discogs Data Processor, living
alongside the existing Python/ttkbootstrap app in DiscogsDataProcessor/.

• No Python runtime required — pure Swift, targets macOS 13+
• Full Fetch → Download → Extract → Convert pipeline, implemented and tested end-to-end
  against real Discogs data
• Resumable, parallel ranged downloads (delegate-based, no byte-by-byte overhead)
• Streaming two-pass XML → CSV converter matching the Python tool's column-flattening
  and repeated-tag/attribute-to-JSON behavior
• Native Core Graphics-based cover art generator with drop-shadow text
• build_app.sh packages the executable into a proper .app bundle (fixes window
  activation glitches from running the raw SwiftPM binary)

This is a preview/in-progress rewrite — UI polish and full feature parity with the
Python version are still ongoing. The Python app remains fully functional and unchanged.

How to run the Swift version

```bash
cd DiscogsDataProcessor
./build_app.sh
open .build/DiscogsDataProcessor.app
```

Requires full Xcode 15+ (not just Command Line Tools).