numa install/uninstall now set/restore system DNS on Windows via
netsh. Parses ipconfig /all per-interface (adapter name, DHCP status,
DNS servers), saves backup to %APPDATA%\numa\original-dns.json, and
restores on uninstall (DHCP or static with secondary servers).
Handles localization (German adapter/DHCP/DNS labels), disconnected
adapters, multiple interfaces, and missing admin privileges. Adds IP
validation to discover_windows() for consistency.
No Windows Service or CA trust yet — user runs numa in a terminal.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
