Add Visual C++ redistributables manifest

Add docs/public/manifest.json containing a JSON array of Visual C++ redistributable package entries. Each entry includes metadata (Name, ProductCode, Version, URI, Release, Architecture), install/uninstall commands and detection files for multiple releases and architectures (2005–2019, x86/x64/ARM64) to be used by installers or tooling that enumerates required runtimes.

Author: aaronparker