Regression: Folder trust changes no longer trigger restart prompt

[Lyonk71]

Issue

When a user changes the folder trust status (from trusted to untrusted or vice versa), the CLI should prompt them to restart to apply the security changes. Currently, the restart prompt never appears because the isRestarting state is hardcoded to false and the logic to detect trust status changes was removed during the UI refactor in PR #5488.

What should happen

When the folder trust status changes, the CLI should:

1. Detect that the trust level has changed from its previous state
2. Set isRestarting to true and keep the dialog open
3. Display the message "To see changes, Gemini CLI must be restarted. Press r to exit and apply changes now."
4. Allow the user to press 'r' to restart the CLI and apply the new trust settings

Currently, the dialog just closes immediately after selection without prompting for a restart, leaving the security changes unapplied.

[gemini-cli]

This issue is a regression, which is a bug. The problem relates to applying folder trust settings, which is a security feature, hence 'area/security-privacy'. The impact is moderate as it affects a security feature but has a simple manual workaround (restarting the CLI), justifying a 'priority/p2'.