Community Contribution License Agreement

By creating this pull request, I grant the project maintainers an unlimited,
perpetual license to use, modify, and redistribute these contributions under any terms they
choose, including both the AGPLv3 and the Fossorial Commercial license terms. I
represent that I have the right to grant this license for all contributed content.

Description

Fixes #16 - UDP port conflict during NAT holepunching on macOS

This PR resolves a race condition where the holepunch goroutine was still holding a UDP port when WireGuard attempted to bind to it, causing "address already in use" errors and forcing unnecessary fallbacks to relay mode.

The fix increases the delay after close(stopHolepunch) from 10ms to 500ms in main.go, giving macOS sufficient time to release the UDP port before WireGuard initialization.

How to test?

1. Run olm with holepunch enabled on macOS:

   sudo -E olm --holepunch

2. Check the logs - you should see successful connection without port errors:

   INFO: WireGuard device created.
   INFO: Peer 1 is now connected (RTT: ~70ms)
   

3. Verify direct connection (not relay) with:

   sudo wg show

   The endpoint should show the peer's actual IP (e.g., 1.2.3.4:65456) not the relay server IP.

4. Without this fix, you would see:

   ERROR: Failed to bring up WireGuard device: listen udp4 :XXXXX: bind: address already in use
   INFO: Adjusted peer 1 to point to relay!