Peers: optional latency check with per-peer setting

The server pings a peer's tunnel address every 30 s and shows the median
of the last 5 minutes in the peer list (with a 1-hour sparkline) and a
24-hour chart on the peer page. Off by default; "active" pings only
while the device sends traffic, "always" keeps the tunnel up.

go.mod

@@ -4,9 +4,11 @@ go 1.27.1
 
 require (
 	github.com/google/nftables v0.3.0
+	github.com/oschwald/maxminddb-golang v1.13.1
 	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
 	github.com/vishvananda/netlink v1.3.1
 	golang.org/x/crypto v0.57.0
+	golang.org/x/net v0.58.0
 	golang.org/x/sys v0.48.0
 	golang.org/x/term v0.46.0
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20241231184526-a9ab2273dd10
@@ -17,9 +19,7 @@ require (
 	github.com/mdlayher/genetlink v1.3.2 // indirect
 	github.com/mdlayher/netlink v1.7.3-0.20250113171957-fbb4dce95f42 // indirect
 	github.com/mdlayher/socket v0.5.1 // indirect
-	github.com/oschwald/maxminddb-golang v1.13.1 // indirect
 	github.com/vishvananda/netns v0.0.5 // indirect
-	golang.org/x/net v0.58.0 // indirect
 	golang.org/x/sync v0.23.0 // indirect
 	golang.org/x/text v0.42.0 // indirect
 	golang.zx2c4.com/wireguard v0.0.0-20231211153847-12269c276173 // indirect