This commit introduces the --me flag, which allows users to quickly display
their current local IPv4 and public IPv4/IPv6 addresses.
The public IPs are retrieved using ifconfig.me via curl, ensuring accurate
detection even in CGNAT or split-DNS scenarios. Local IPv4 is determined
via the system's active route through the configured resolver.
The output also includes a CGNAT detection based on private IP ranges and
the reserved 100.64.0.0/10 block, providing a helpful warning if detected.
IPv6 privacy extensions are common, so local IPv6 detection has been removed
to avoid redundant or unstable information.
