core tests: migrate rmcp turns to profiles

[bolinfest]

Summary

• Removes SandboxPolicy from the RMCP client test suite.
• Adds shared read-only user-turn helpers that submit PermissionProfile::read_only() plus the legacy compatibility projection required by the current Op::UserTurn shape.
• Keeps sandbox metadata assertions intact by deriving the expected legacy sandboxPolicy value from the same read-only profile used for the turn.

Verification

• cargo check -p codex-core --tests
• just fmt

[chatgpt-codex-connector]

💡 Codex Review

codex/codex-rs/tui/src/chatwidget.rs

Lines 9813 to 9816 in c30257d

	) && !current_permission_profile
	.file_system_sandbox_policy()
	.can_write_path_with_cwd(cwd, cwd)
	&& current_permission_profile.network_sandbox_policy()

Don't mark read-only current when other write roots are allowed

The read-only branch in preset_matches_current only checks whether cwd is writable, so a managed profile that can write outside cwd (for example, a custom profile with write access to /tmp/cache but not the workspace root) is incorrectly treated as read-only. This causes /permissions to show the wrong current preset and can mislead users about the session's effective write access.

---

codex/codex-rs/tui/src/app/platform_actions.rs

Lines 26 to 28 in c30257d

	let Ok(sandbox_policy) = permission_profile.to_legacy_sandbox_policy(cwd.as_path())
	else {
	tx.send(AppEvent::OpenWorldWritableWarningConfirmation {

Keep compatibility projection for Windows world-writable scans

This path now fails closed when PermissionProfile::to_legacy_sandbox_policy returns an error, but non-legacy managed profiles are expected to hit that conversion path and were previously scanned via a compatibility sandbox projection. On Windows, those profiles will now always trigger failed_scan warnings/fallback prompts even when a compatible scan policy could be derived, creating noisy false failures for valid configurations.

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