Function resolve_binary 

pub fn resolve_binary(
    explicit: Option<&Path>,
    path: Option<&str>,
    home_dir: &Path,
) -> Result<PathBuf, ToolError>

Explicit path; else the first opencode/opencode.exe on path (on Windows also the executable behind an npm opencode.cmd shim, see npm_shim_exe); else <home>/.opencode/bin/opencode[.exe]; else OPENCODE_NOT_FOUND. Pure: nothing is spawned.