[Plugin] Add Sfizioso Player

[kmturley]

Adds Sfizioso Player 0.11.0 to the registry.

All requirements from the upstream tracking issue are now met:

• License: dual-licensed, BSD-2-Clause (shared libs) / AGPL-3.0 (the player app itself) — agpl-3.0 used here since that governs the distributed plugin/app.
• Release: v0.11.0 has real binaries (sfizioso-player-linux.tar.gz, sfizioso-player-macos.tar.gz, sfizioso-player-windows.zip).
• Preview image: added to the README by the maintainer in rullopat/sfizioso-player@584266f.

Verified file contents by extracting each archive:

• Linux: VST3 + Standalone (x64)
• macOS: VST3 + AU (component) + Standalone app (arm64 only, confirmed via file)
• Windows: VST3 + Standalone exe (x64)

Closes rullopat/sfizioso-player#3

[github-actions]

VirusTotal Report:

• test/downloads/rullopat/sfizioso-player/0.11.0/2-sfizioso-player-windows.zip
• test/downloads/rullopat/sfizioso-player/0.11.0/1-sfizioso-player-macos.tar.gz
• test/downloads/rullopat/sfizioso-player/0.11.0/0-sfizioso-player-linux.tar.gz

[github-actions]

Destination urls:
Registry: https://open-audio-stack.github.io/open-audio-stack-registry/plugins/rullopat/sfizioso-player
Site: https://studiorack.github.io/studiorack-site/plugins/rullopat/sfizioso-player

[github-actions]

Plugin author notification:

@rullopat — your plugin has been submitted to the Open Audio Stack registry. Please review this PR and let us know if the metadata (name, description, tags, files) is correct. To see a full list of all currently added plugins, click here.