fix: translate xp path if using SSHStateProvider

[VictorMorand]

This ends fixing #213 by providing xp path translation when using SSHStateProvider.

Summary of Changes

1. Core API: Added translate_path(path: Path) -> str to the StateProvider base class. This provides a standard way to
   convert internal filesystem paths into user-facing display paths.
2. Remote Support: Implemented translate_path in SSHStateProviderClient. It now automatically detects if a path resides within the local SSH cache and translates it back to the corresponding path in the remote_workspace.
3. TUI Fix: Updated the ExperimentsList widget's action_copy_path to use this translation service. This fixes the bug
   where pressing 'f' would copy a temporary local cache path instead of the actual remote path.
4. Consistency: Refactored get_display_path (used by Tasks) to use this new centralized translation logic, ensuring
   consistent behavior across all TUI components.
5. Validation: Added unit tests in test_path_translation.py covering both local and remote path translation scenarios.

These changes ensure that "Copy Path" always returns a meaningful path to the user, regardless of whether the experiment is running locally or on a remote cluster.