Function build_aur_install 

pub fn build_aur_install<S: AsRef<str>>(
    helper: AurHelper,
    names: &[S],
    options: &InstallOptions,
) -> Result<CommandSpec>

What: Build an AUR helper install command for AUR packages.

Inputs:

• helper: The AUR helper to use (from caller config or super::detect_aur_helper).
• names: AUR package names to install (validated).
• options: Flag options (needed, noconfirm, aur_only).

Output:

• Ok(CommandSpec) like paru -S --aur --needed --noconfirm -- <names...>.

Details:

• --aur (when options.aur_only) ensures helpers do not prefer a sync database (e.g., Chaotic-AUR) when the same name exists on the AUR — matching Pacsea’s aur_install_helper_flags.
• A -- operand terminator separates flags from package names; paru and yay forward it to pacman-style operand parsing.
• AUR helpers must NOT run under sudo; they invoke sudo themselves for the pacman step. Do not wrap the result in with_privilege.

Errors

Returns ArchToolkitError::InvalidPackageName when a name fails validation, or ArchToolkitError::EmptyInput when names is empty.

Example

use arch_toolkit::install::build_aur_install;
use arch_toolkit::types::install::{AurHelper, InstallOptions};

let spec = build_aur_install(AurHelper::Paru, &["yay-bin"], &InstallOptions::default())?;
assert_eq!(spec.to_shell_string(), "paru -S --aur --needed --noconfirm -- yay-bin");