feat: Add Ruby windows support

[Goldziher]

Ruby bindings are currently unavailable on Windows due to build issues with mingw.

Problem

The Ruby build fails on Windows with mingw toolchain.

Solution

Fix the mingw build configuration to enable Ruby bindings on Windows.

Context

• Related to Ruby bindings development
• Requires mingw build system knowledge
• Windows platform specific issue

[numericals-org]

Hi! I’d like to work on fixing the MinGW build configuration for the Ruby bindings on Windows.

I’ll set up a Windows + MinGW environment, reproduce the build failure, and investigate what changes are needed to make the Ruby bindings compile successfully.

Any guidance on the preferred build setup or known problem areas would be appreciated.

[numericals-org]

Morning @Goldziher
docs: document Windows (MSYS2 + MinGW) Ruby build issues and blockers

This commit documents the issues encountered when attempting to build
the Ruby bindings on Windows using MSYS2 + MinGW.

Observed Windows / project-related problems:

1. task setup fails because uv is not installed or documented:
   "uv": executable file not found in $PATH

2. Because setup fails, the Rust core is not vendored into:
   packages/ruby/vendor/kreuzberg

3. As a result, Ruby native compilation fails with:
   failed to read .../vendor/kreuzberg/Cargo.toml
   The system cannot find the path specified (os error 3)

4. The build system assumes cargo is available in MSYS2, but this
   requires installing mingw-w64-x86_64-rust, which is not documented.

5. The Ruby build process depends on git ls-files, but Git is not
   guaranteed to be installed in the MSYS2 environment.

6. Windows path and environment differences (MSYS2 vs native Windows)
   cause setup and build steps to fail silently or behave differently
   from Linux/macOS.

Issues that were resolved during setup (environment-related):

• Installed Visual Studio C++ tools to fix missing MSVC linker
• Installed cargo-task to enable task commands
• Switched to MSYS2 MINGW64 to access gcc/ruby/cmake
• Installed mingw-w64-x86_64-rust so cargo is available in MSYS2
• Installed Ruby gems with bundle install
• Installed Git inside MSYS2
• Ran Bundler from the correct directory (packages/ruby)

Remaining problems that affect Windows support:

• task setup does not complete due to missing uv
• Rust core is not vendored on Windows
• Ruby native bindings cannot compile as a result
• Windows-specific setup requirements are not documented

This commit asks whether these failures are expected limitations of
Windows support, or if the documentation and setup process should be
improved (e.g., explicitly requiring uv, MSYS2 Rust, and MSYS2 Git).

[Goldziher]

By all means, PR welcome 🤗

[Goldziher]

Ok, i see a PR is not materializing so leaving this open. Fix by anyone is welcome.