Support exact argv in the Rust streaming runner on Windows

[konard]

Reproduction

The published Rust crate (command-stream@0.15.0) exposes StreamingRunner::new(command: String). It launches /bin/sh -c on POSIX and cmd.exe /c on Windows. The public command_stream::quote helper emits POSIX single-quote escaping:

assert_eq!(command_stream::quote("hello world"), "'hello world'");

cmd.exe does not treat single quotes as quoting, so a downstream consumer cannot safely preserve an exact executable-plus-argv boundary on Windows through the streaming API. This is especially problematic for arguments containing spaces or shell metacharacters.

Requested interface

Please add an argv-safe streaming constructor/builder accepting an executable and argument vector directly, or provide shell-specific Windows quoting which safely survives the cmd.exe /c layer.

Downstream workaround

link-assistant/formal-ai#990 uses StreamingRunner plus the crate's quoting helper on POSIX and temporarily retains its prior exact-argv std::process::Command runner on Windows.