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

從 dotnet publish -p:PublishAot=true 情境以及連結的 Microsoft Docs Native AOT 互通參考開始。確定 LibGit2Sharp 如何公開 NativeLibrary/DirectPInvoke 中繼資料，並將其封裝以用於靜態 libgit2 連結。完成的標準是，NativeAOT publish 產生一個可執行檔，而不需要獨立的 libgit2 DLL、.so 或 .dylib。