Add port 0 validation for IPv6 addresses

Co-authored-by: Byron <63622+Byron@users.noreply.github.com>

Author: Copilot

gix-url/src/simple_url.rs

@@ -121,6 +121,10 @@ impl<'a> ParsedUrl<'a> {
                     let port = port_str
                         .parse::<u16>()
                         .map_err(|_| ParseError::InvalidPort)?;
+                    // Validate port is in valid range (1-65535, port 0 is invalid)
+                    if port == 0 {
+                        return Err(ParseError::InvalidPort);
+                    }
                     return Ok((host, Some(port)));
                 } else {
                     return Err(ParseError::InvalidDomainCharacter);