Nicer pqxx::connection::port().

[jtv]

When I wrote that function, a nullable pointer was still a reasonable way to represent an optional integer. Nowadays we have std::optional<int>. Just a shame that we can't give the new function the same name.

[Copilot]

Pull request overview

This PR modernizes the pqxx::connection::port() API by introducing a new port_number() method that returns std::optional<int> instead of a nullable C-style string pointer. The old port() method is deprecated but remains functional for backward compatibility.

• Adds new port_number() method returning std::optional<int>
• Deprecates the existing port() method that returns char const *
• Updates tests to use the new API while maintaining compatibility testing

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

File	Description
include/pqxx/connection.hxx	Marks port() as deprecated and declares new port_number() method with std::optional<int> return type
src/connection.cxx	Implements port_number() to parse port string and return optional integer
test/test_connection.cxx	Tests both deprecated and new APIs for closed connection scenario
test/test21.cxx	Wraps deprecated port() usage with ignore-deprecated pragmas