CATalog v0.1.0 (test build)

Test build, not tried on a real large library. The window is a plain list for now (the designed window is only in the mockup). One zip: installers for Windows (.exe), macOS (.pkg), Linux (Flatpak extensions and a plain .vst3), the PDF manual and INSTALL.txt. Everything works offline. SHA-256 sums are inside the zip.