Replace manual COM pointers with wil::com_ptr

[asklar]

Summary:

• Replaced owned raw COM members and locals in the XAML TAP DLL with wil::com_ptr, including site/diagnostics/visual-tree-service ownership and class factory temporary ownership.
• Replaced WPF TAP CLR hosting COM locals with wil::com_ptr.
• Linked WIL into TAP targets that now include wil/com.h, without changing /MT or cppwinrt/Windows SDK logic.

Deliberately left raw:

• XAML diagnostics callback/interface parameters and QueryInterface out-parameters remain raw because they are non-owning COM ABI boundaries.
• GetIInspectableFromHandle handling remains raw to preserve existing XAML diagnostics ABI lifetime behavior in the injected TAP DLL.

Validation:

• dotnet build src\tap_wpf\LvtWpfTap.csproj -c Release
• dotnet build src\plugin_avalonia\LvtAvaloniaTreeWalker\LvtAvaloniaTreeWalker.csproj -c Release
• cmake --build build
• build\lvt_unit_tests.exe
• build\lvt.exe --pid --frameworks

Fixes #10