Function get_pkgbuild_from_cache 

pub fn get_pkgbuild_from_cache(name: &str) -> Option<String>

What: Get PKGBUILD from yay/paru cache (offline method).

Inputs:

• name: Package name.

Output:

• Returns PKGBUILD content if found in cache, or None.

Details:

• Checks yay cache (/.cache/yay) and paru cache (/.cache/paru).
• Also tries using yay -G or paru -G commands.