3153b7e8a3
Fixes interface auto-detection failures on Pi Zero 2W where wlan0 doesn't exist at boot. Implementation: - Added detect_interface_with_retry() function with 3x retry fallback chain - Config-supplied interface preferred, then /proc/net/route, then UP interface - Exponential backoff: 5s, 10s, 20s delays between retries - Filters excluded prefixes: lo, tailscale*, wg*, tun*, docker*, veth*, br-* - Used in Engine.__init__(), PacketCapture.start(), MacManager.start() - Full test coverage: 10 tests for detection, backoff, filtering Addresses issue where network stack initializes after boot and interfaces become available after 5-10 second delay.