Fix dns_apply_windows build errors in adapter lookup; adapter discovery & UI improvements

[Abhijrathod]

Motivation

• Resolve compilation failures caused by missing Windows networking symbols and inconsistent include ordering in cpp_core/src/dns_apply_windows.cpp.
• Preserve and improve adapter discovery so disabled/disconnected adapters remain visible to the UI while prioritizing connected adapters.
• Improve UX clarity by surfacing adapter state, DNS summaries, and a visible app version in the UI.

Description

• Fixed include ordering and portability in cpp_core/src/dns_apply_windows.cpp by adding #define WIN32_LEAN_AND_MEAN and including winsock2.h/ws2tcpip.h before windows.h, and replaced GAA_FLAG_INCLUDE_PREFIX with 0 in GetAdaptersAddresses calls to avoid SDK-dependent symbol issues while keeping adapter enumeration logic.
• Implemented NormalizeGuid + FindAdapterFriendlyName helpers and use adapter friendly name (when available) as a netsh selector and updated netsh commands to use interface ipv4 set dnsservers / add dnsservers / source=dhcp syntax for more reliable execution.
• Adjusted cpp_core/src/network_windows.cpp to skip only loopback adapters so disabled/disconnected adapters remain visible to the UI.
• Updated UI and viewmodel: added AdapterState and DnsSummary properties in windows_gui/Models/NetworkModel.cs, showed a version badge and helper text in windows_gui/MainWindow.xaml, and changed selection/guardrail logic in windows_gui/ViewModels/MainViewModel.cs to prefer connected adapters and prevent apply/restore on disabled adapters.
• Bumped WPF project metadata version fields in windows_gui/DNSChanger.csproj and added a short release note in README.md under Latest changes (v2.1.0).

Testing

• Ran static inspections and pattern checks such as rg -n "GAA_FLAG_INCLUDE_PREFIX|GetAdaptersAddresses|winsock2" and inspected the modified file with nl to verify the include/order and flag changes succeeded.
• Confirmed the GetAdaptersAddresses calls no longer reference the undefined macro and that adapter-friendly-name lookup code is present by file inspection.
• A full Windows/MSVC build and WPF dotnet build were not executed in this environment due to the container/tooling limitations, so no end-to-end binary build was produced here.

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Codex Task

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Distinguish disabled adapters from disconnected ones

This new guard blocks DNS changes for every network where IsEnabled is false, but in cpp_core/src/network_windows.cpp both isEnabled and isConnected are derived from adapter->OperStatus == IfOperStatusUp. In practice, enabled-but-disconnected adapters (for example an unplugged Ethernet NIC) report OperStatus down, so they are mislabeled as disabled and users are prevented from apply/restore operations even though the change is intended to block only truly disabled adapters.

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