microsoft/vcpkg ? reverse-engineered prompt

Build me a cross platform C and C++ package manager like vcpkg that helps developers install libraries and wire them into their projects easily on Windows, macOS, and Linux.

It should support both a manifest based workflow for project dependencies and a simpler command line install flow, and it should work nicely with common build systems like CMake and MSBuild. I want the tool to let people add packages, manage versions, reuse downloaded or built artifacts with caching, and handle offline or locked down environments as well as possible. It should also have a way to package and publish new libraries into a registry, since I want this to be useful for both using open source packages and contributing new ones.

Please make it feel like a real developer tool, with helpful commands, clear setup steps, and enough documentation or help output that someone can get started quickly. If you need to check current docs or behavior, look them up online first.