Rewrite Strix from scratch as single binary

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

pkg/probe/mdns.go

@@ -0,0 +1,137 @@
+package probe
+
+import (
+	"context"
+	"net"
+	"strings"
+	"time"
+
+	"github.com/miekg/dns"
+)
+
+const (
+	hapService = "_hap._tcp.local."
+
+	txtCategory    = "ci"
+	txtDeviceID    = "id"
+	txtModel       = "md"
+	txtStatusFlags = "sf"
+
+	statusPaired     = "0"
+	categoryCamera   = "17"
+	categoryDoorbell = "18"
+)
+
+// QueryHAP sends unicast mDNS query to ip:5353 for HomeKit service.
+// Returns nil if device is not a HomeKit camera/doorbell.
+func QueryHAP(ctx context.Context, ip string) (*MDNSResult, error) {
+	msg := &dns.Msg{
+		Question: []dns.Question{
+			{Name: hapService, Qtype: dns.TypePTR, Qclass: dns.ClassINET},
+		},
+	}
+
+	query, err := msg.Pack()
+	if err != nil {
+		return nil, err
+	}
+
+	conn, err := net.ListenPacket("udp4", ":0")
+	if err != nil {
+		return nil, err
+	}
+	defer conn.Close()
+
+	deadline, ok := ctx.Deadline()
+	if !ok {
+		deadline = time.Now().Add(100 * time.Millisecond)
+	}
+	_ = conn.SetDeadline(deadline)
+
+	addr := &net.UDPAddr{IP: net.ParseIP(ip), Port: 5353}
+	if _, err = conn.WriteTo(query, addr); err != nil {
+		return nil, err
+	}
+
+	buf := make([]byte, 1500)
+	n, _, err := conn.ReadFrom(buf)
+	if err != nil {
+		return nil, nil // timeout = not a HomeKit device
+	}
+
+	var resp dns.Msg
+	if err = resp.Unpack(buf[:n]); err != nil {
+		return nil, nil
+	}
+
+	return parseHAPResponse(&resp)
+}
+
+// internals
+
+func parseHAPResponse(msg *dns.Msg) (*MDNSResult, error) {
+	records := make([]dns.RR, 0, len(msg.Answer)+len(msg.Extra))
+	records = append(records, msg.Answer...)
+	records = append(records, msg.Extra...)
+
+	var ptrName string
+	for _, rr := range records {
+		if ptr, ok := rr.(*dns.PTR); ok && ptr.Hdr.Name == hapService {
+			ptrName = ptr.Ptr
+			break
+		}
+	}
+	if ptrName == "" {
+		return nil, nil
+	}
+
+	// ex. "My Camera._hap._tcp.local." -> "My Camera"
+	var name string
+	if i := strings.Index(ptrName, "."+hapService); i > 0 {
+		name = strings.ReplaceAll(ptrName[:i], `\ `, " ")
+	}
+
+	info := map[string]string{}
+	for _, rr := range records {
+		txt, ok := rr.(*dns.TXT)
+		if !ok || txt.Hdr.Name != ptrName {
+			continue
+		}
+		for _, s := range txt.Txt {
+			k, v, _ := strings.Cut(s, "=")
+			info[k] = v
+		}
+		break
+	}
+
+	category := info[txtCategory]
+	if category != categoryCamera && category != categoryDoorbell {
+		return nil, nil
+	}
+
+	categoryName := "camera"
+	if category == categoryDoorbell {
+		categoryName = "doorbell"
+	}
+
+	var port int
+	for _, rr := range records {
+		if srv, ok := rr.(*dns.SRV); ok && srv.Hdr.Name == ptrName {
+			port = int(srv.Port)
+			break
+		}
+	}
+
+	return &MDNSResult{
+		Name:     name,
+		DeviceID: info[txtDeviceID],
+		Model:    info[txtModel],
+		Category: categoryName,
+		Paired:   info[txtStatusFlags] == statusPaired,
+		Port:     port,
+	}, nil
+}
+
+func init() {
+	dns.Id = func() uint16 { return 0 }
+}