Standardize permission-action vocabulary in the setup wizard

[malpern]

Current behavior

The Accessibility and Input Monitoring pages use Turn On, Add in Settings, and Open Settings Manually for related permission actions. The underlying flows are now distinct and reliable, but the labels do not consistently explain which action will occur.

Narrow scope

Standardize copy on the two permission pages without changing permission detection, polling, deep links, drag-to-authorize behavior, or installer execution:

• Turn On — KeyPath will ask macOS for permission automatically.
• Add in Settings — the app or engine must be added manually or through the drag-to-authorize flow.
• Open Settings — navigation only; no automatic request or add operation.

Keep helper and DriverKit terminology out of this slice because those actions have different semantics.

Acceptance criteria

• Equivalent actions use equivalent labels on Accessibility and Input Monitoring pages.
• A label never promises an automatic action when the button only opens System Settings.
• Existing accessibility identifiers remain stable.
• Focused wizard tests or snapshots pin the copy/state mapping.
• No installer, permission-oracle, or runtime behavior changes.

Priority

Valid polish, but not a prerequisite for the 1.1 dependency graph. Keep on hold unless clean-account testing shows the wording causes a real setup failure.

Split from #934.