Function version_satisfies 

pub fn version_satisfies(installed: &str, requirement: &str) -> bool

What: Perform a simplified comparison between an installed version and a requirement expression.

Inputs:

• installed: Version string currently present on the system.
• requirement: Comparison expression such as >=1.2 or =2.0.

Output:

• true when the expression evaluates in favor of the installed version; otherwise false.

Details:

• Uses straightforward string comparisons rather than full semantic version parsing, matching pacman’s format.