feat(macOS): Add trash sync toggle for FileProvider virtual files

[Flo-129]

Summary

• Add user-configurable option to enable/disable macOS Trash integration for FileProvider domains
• When enabled: deleted files go to macOS Trash, server trash visible in Finder
• When disabled: Finder shows "Delete Immediately" (files still recoverable from server)

Changes

• New "Integrate macOS Trash" checkbox in Virtual Files settings (macOS 13.0+)
• Per-account preference stored in NSUserDefaults
• Domain reconfiguration via remove/add cycle (supportsSyncingTrash is read-only after creation)
• Thread-safety improvements for concurrent domain registry access
• Cleanup of unused socket communication code (superseded by XPC)

Test plan

• Enable virtual files for an account
• Toggle "Integrate macOS Trash" option on
• Delete a file in Finder → verify it appears in macOS Trash
• Open Trash in Finder → verify server trash contents are visible
• Toggle option off → verify no crash occurs
• Delete a file → verify "Delete Immediately" behavior

Requirements

• macOS 13.0+ (option hidden on earlier versions)
• Virtual files must be enabled for the account

[i2h3]

Thank you for your new pull request! I will bring this up for discussion internally. 🤔 Personally, I think it is fine to have a checkbox for that feature toggle but it contradicts our design guidelines on the other hand. 😵‍💫 I need to check in with the others.

[oskardotglobal]

Could ya'll approve workflows so we can test the builds from CI?

[github-actions]

Artifact containing the AppImage: nextcloud-appimage-pr-9264.zip

Digest: sha256:e7eddbec74c0a8cb15dc350e6f59af362c26cc88e549cdfb407538f81e1bec9b

To test this change/fix you can download the above artifact file, unzip it, and run it.

Please make sure to quit your existing Nextcloud app and backup your data.

[github-actions]

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