## What changed
- Add `in_app_browser.allow_external_browser_settings_import` to managed requirements, preserving explicit Boolean values through layered composition while leaving an omitted value unset.
- Return the policy as `inAppBrowser.allowExternalBrowserSettingsImport` from `configRequirements/read` and include it in the generated protocol schemas.
- Keep the import policy independent from the in-app browser feature flag and agent Browser Use requirements.
## Testing
- Cover parsing, managed-layer precedence, invalid values, user and session override resistance, and app-server response serialization.
GitOrigin-RevId: efa2621d2b1cf503f1bee2505d9914cb4fb7221d