NetDNS2 bundled for Watch My Domains SED

Source repository:
https://github.com/mikepultz/netdns2

License:
See LICENSE file in this directory.

Purpose:
NetDNS2 is bundled to provide deterministic DNS and AXFR functionality
without relying on system-installed PHP libraries or PEAR.

Integration notes:
- This library is loaded explicitly by SED bootstrap code.
- It is not handled by the SED namespace-based autoloader.
- Directory layout matches upstream src/NetDNS2 structure.

Do not modify this library directly unless updating from upstream.
