Enable static linking of libgit2 (NativeLibrary / DirectPInvoke) for NativeAOT builds

Overview
Publishing with dotnet publish -p:PublishAot=true (NativeAOT) currently leaves the libgit2 native DLL/so/dylib in the output folder, preventing a true single-file distribution. If LibGit2Sharp exposed NativeLibrary / DirectPInvoke metadata to let the linker embed a static libgit2, NativeAOT users could ship just one executable.

Problems

• NativeAOT disables the single-file bundler, so IncludeNativeLibrariesForSelfExtract is ignored and the native library is always emitted next to the .exe.
• Distributors must ship extra files, and there is no self-extract logic at runtime.

Request
Please add official support for statically linking libgit2 when LibGit2Sharp is used with NativeAOT (for example, by publishing a package that injects the required NativeLibrary metadata).

Reference

• Microsoft Docs — “Native AOT interop”
  https://learn.microsoft.com/en-us/dotnet/core/deploying/native-aot/interop

从 dotnet publish -p:PublishAot=true 场景以及链接的 Microsoft Docs Native AOT 互操作参考开始。确定 LibGit2Sharp 如何公开 NativeLibrary/DirectPInvoke 元数据，并将其打包用于静态 libgit2 链接。完成的标准是，NativeAOT publish 生成一个可执行文件，而不需要单独的 libgit2 DLL、.so 或 .dylib。