Ignore macOS, Xcode user data, build output, SwiftPM and Reality
Composer Pro user files; remove already tracked xcuserdata and
rcuserdata from the index (files stay on disk).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Introduce TankDefinition/TankCatalog loaded from Tanks.json, bundle the
Drachengas USDZ tank models, add tank selection and preview views, and
update the AR experience, editor and project views to use the catalog.
Includes tests for catalog loading and model selection.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
