Return the fixed managed-config path and whether it is authoritative.
What the snapshot loader reads. Callers that report health need this rather
than managed_config_path, so a guessed path is never mistaken for an
authoritative one.
Override the detected platform; intended for tests.
Test-only injection point for the Windows branch. Production
passes None so the ProgramData directory comes from the registry.
Passing a real environment restores the redirection this module
exists to prevent.
