Radio Galaxy FX auth/API path fixes

Applied fixes:
- admin/login.php
  External auth path now points to:
  C:/inetpub/Authentication/radiogalaxyfx/auth_config.php

- admin/users.php
  External auth write path now points to:
  C:/inetpub/Authentication/radiogalaxyfx/auth_config.php

- admin/westats.php
  External API config path now points to:
  C:/inetpub/Authentication/api/radiogalaxyfx.php

Notes:
- Forward slashes were used in PHP paths for Windows compatibility.
- PHP syntax rechecked after patching.
