Add ONVIF probe detector via unicast WS-Discovery

- Add ProbeONVIF() prober: sends unicast WS-Discovery to ip:3702,
  parses XAddrs, Name, Hardware from response (no auth needed)
- Add ONVIFResult struct to probe models
- Register ONVIF detector with highest priority (before HomeKit)
- Fix homekit.html back-wrapper max-width to match design system

pkg/probe/models.go

@@ -14,6 +14,7 @@ type Probes struct {
 	ARP   *ARPResult   `json:"arp"`
 	MDNS  *MDNSResult  `json:"mdns"`
 	HTTP  *HTTPResult  `json:"http"`
+	ONVIF *ONVIFResult `json:"onvif"`
 }
 
 type PortsResult struct {
@@ -43,3 +44,10 @@ type HTTPResult struct {
 	StatusCode int    `json:"status_code"`
 	Server     string `json:"server"`
 }
+
+type ONVIFResult struct {
+	URL      string `json:"url"`
+	Port     int    `json:"port"`
+	Name     string `json:"name,omitempty"`
+	Hardware string `json:"hardware,omitempty"`
+}