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/ping.go

@@ -0,0 +1,39 @@
+package probe
+
+import (
+	"context"
+	"net"
+	"time"
+)
+
+func CanICMP() bool {
+	conn, err := net.DialTimeout("ip4:icmp", "127.0.0.1", 100*time.Millisecond)
+	if err != nil {
+		return false
+	}
+	conn.Close()
+	return true
+}
+
+func Ping(ctx context.Context, ip string) (*PingResult, error) {
+	deadline, ok := ctx.Deadline()
+	if !ok {
+		deadline = time.Now().Add(100 * time.Millisecond)
+	}
+
+	timeout := time.Until(deadline)
+	if timeout <= 0 {
+		return nil, context.DeadlineExceeded
+	}
+
+	start := time.Now()
+	conn, err := net.DialTimeout("ip4:icmp", ip, timeout)
+	if err != nil {
+		return nil, err
+	}
+	conn.Close()
+
+	return &PingResult{
+		LatencyMs: float64(time.Since(start).Microseconds()) / 1000.0,
+	}, nil
+}