ICMP requires root or CAP_NET_RAW which is not available in
unprivileged containers. Probe now relies solely on port scanning
for reachability detection, which works without any special
permissions. Add port 51826 (HomeKit) to both default and
database-loaded port lists.
Complete architecture rewrite following go2rtc patterns:
- pkg/ for pure logic (camdb, tester, probe, generate)
- internal/ for application glue with Init() modules
- Single HTTP server on :4567 with all endpoints
- zerolog with password masking and memory ring buffer
- Environment-based config only (no YAML files)
API endpoints: /api/search, /api/streams, /api/test,
/api/probe, /api/generate, /api/health, /api/log
Dependencies: go2rtc v1.9.14, go-sqlite3, miekg/dns, zerolog