Export two pickup icons

Start with: examples/svarn/pickups.png (a fictional 32 × 16 image with a coin and a gem) and examples/svarn/slices.csv, which lists the two slices to draw: coin at x 0, y 0, 16 × 16 and gem at x 16, y 0, 16 × 16.

1. In Aseprite open examples/svarn/pickups.png.
2. With Aseprite's Slice tool draw the two slices from slices.csv and name them coin and gem in each slice's properties.
3. Save the sprite with File › Save As… as pickups.aseprite (the .aseprite format keeps slices).
4. From the File menu choose Svarn: Batch Export Slices... and keep All slices, All frames, profile slice_frame and Frame digits 2. Click Use document folder, then Preview, then Export.

Expected result: Preview plans 2 PNG files (coin, frame 1 -> coin_01.png and gem, frame 1 -> gem_01.png). Export creates a folder pickups-slices-001 next to pickups.aseprite containing coin_01.png and gem_01.png (16 × 16 each) and svarn-manifest.json with status complete; the Status row reads Exported and verified 2 of 2 files in pickups-slices-001. Exporting again creates pickups-slices-002 instead of overwriting.

All examples are fictional or synthetic.
