When the scanner hits a permission-denied error (TCC-protected
directories on macOS without Full Disk Access, or any other EPERM),
the error now names the offending path and includes platform-specific
remediation instructions. On macOS it points the user at System
Settings -> Privacy & Security -> Full Disk Access. On other
platforms it suggests --skip-errors.
The error wraps os.ErrPermission so errors.Is still works for callers
that care about the underlying error.
README quickstart and snapshot create docs now mention the macOS FDA
requirement.
