Remove ICMP ping from probe, add HomeKit port 51826

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.

pkg/probe/models.go

@@ -3,14 +3,12 @@ package probe
 type Response struct {
 	IP        string  `json:"ip"`
 	Reachable bool    `json:"reachable"`
-	LatencyMs float64 `json:"latency_ms,omitempty"`
-	Type      string  `json:"type"` // "unreachable", "standard", "homekit"
+	Type string `json:"type"` // "unreachable", "standard", "homekit"
 	Error     string  `json:"error,omitempty"`
 	Probes    Probes  `json:"probes"`
 }
 
 type Probes struct {
-	Ping  *PingResult  `json:"ping"`
 	Ports *PortsResult `json:"ports"`
 	DNS   *DNSResult   `json:"dns"`
 	ARP   *ARPResult   `json:"arp"`
@@ -18,10 +16,6 @@ type Probes struct {
 	HTTP  *HTTPResult  `json:"http"`
 }
 
-type PingResult struct {
-	LatencyMs float64 `json:"latency_ms"`
-}
-
 type PortsResult struct {
 	Open []int `json:"open"`
 }

pkg/probe/ping.go

@@ -1,39 +0,0 @@
-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
-}