Enable cask FFI helpers for all users

[MikeMcQuaid]

• avoid requiring Swift and developer tools for cask quarantine, xattr copying and Trash operations
• remove the completed developer rollout gates, TODOs and obsolete Swift fallback scripts
• keep quarantine diagnostics focused on the remaining xattr dependency

Fixes #23029

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Codex 5.6 Sol max with local review and testing.

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