[AdamMagued]

Resolves #273

Summary

Implement dynamic TLS certificate reloading via tls.Config.GetCertificate to automatically reload updated certificate and key files from disk without restarting the server.

• Check certificate and private key file modification times and sizes on TLS handshakes.
• Fall back safely to existing valid in-memory certificate if a reload encounters transient file errors during disk writes.
• Support direct file replacement, atomic renames, and symlink targets (such as Kubernetes secret rotations).
• Tested in isolated container sandbox across initial loading, dynamic updates, error fallback, symlinks, concurrent handshakes, and live HTTPS connections.