fix: null gateway latency; skip aiwanbal generic modem_type for carrier detection

- Gateway ping latency is LAN RTT (<1ms), not WAN latency; set to null so
  dashboards don't show misleading sub-ms values for Eyeride-NAT'd interfaces
- aiwanbal reports modem_type=generic for wired ISP ports; treat same as none
  so carrier detection falls through to gateway IP pattern matching (AT&T etc.)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package/kit-busrouter/files/usr/lib/busrouter/telemetry-synology.sh

@@ -207,6 +207,7 @@ _detect_wan_roles() {
 _aiwanbal_available() {
 	[ -d "$AIWANBAL_DIR" ] || return 1
 	_mtime=$(stat -c %Y "${AIWANBAL_DIR}/wan1_score_avg" 2>/dev/null || stat -f %m "${AIWANBAL_DIR}/wan1_score_avg" 2>/dev/null)
+	_mtime=$(printf '%s' "$_mtime" | tr -cd '0-9')
 	[ -n "$_mtime" ] || return 1
 	_now=$(date +%s)
 	_age=$(( _now - _mtime ))
@@ -238,6 +239,20 @@ _ping_iface() {
 	# Extract loss
 	_loss=$(echo "$_out" | sed -n 's/.* \([0-9]*\)% packet loss.*/\1/p')
 	[ -z "$_loss" ] && _loss="null"
+	# If ICMP to internet gives 100% loss, ping the local gateway —
+	# Eyeride NAT drops internet ICMP but the gateway (192.168.10.1) is reachable locally.
+	if [ "$_loss" = "100" ]; then
+		_gw=$(ip route show 2>/dev/null | grep "dev $_iface" | grep -v "^default" | awk '/via/{print $3; exit} /kernel/{print ""}' | head -1)
+		[ -z "$_gw" ] && _gw=$(ip route show default 2>/dev/null | grep "dev $_iface" | awk '{print $3}' | head -1)
+		if [ -n "$_gw" ]; then
+			_gw_out=$(ping -c 3 -W 2 "$_gw" 2>/dev/null)
+			_gw_loss=$(echo "$_gw_out" | sed -n 's/.* \([0-9]*\)% packet loss.*/\1/p')
+			if [ -n "$_gw_loss" ] && [ "$_gw_loss" != "100" ]; then
+				_loss="$_gw_loss"
+				_avg="null"   # gateway RTT is LAN latency, not meaningful as WAN metric
+			fi
+		fi
+	fi
 	printf '%s %s %s\n' "${_avg}" "${_jitter}" "${_loss}" | tr -d '\n\r'
 }
 
@@ -292,8 +307,8 @@ _collect_wan() {
 			_dl=$(echo "$_st" | awk '{print $1}')
 			_ul=$(echo "$_st" | awk '{print $2}')
 		fi
-		[ -z "$_dl" ] || [ "$_dl" = "0" ] && _dl="0.0"
+		[ -n "$_dl" ] || _dl="0.0"
-		[ -z "$_ul" ] || [ "$_ul" = "0" ] && _ul="0.0"
+		[ -n "$_ul" ] || _ul="0.0"
 	fi
 
 	printf '{"score":%s,"latency_ms":%s,"dl_mbps":%s,"ul_mbps":%s,"jitter_ms":%s,"loss_pct":%s}' \
@@ -319,7 +334,7 @@ _detect_carrier() {
 	for _n in 1 2; do
 		_mod=$(_read_file "${AIWANBAL_DIR}/wan${_n}_modem_type" 2>/dev/null)
 		_active=$(_read_file "${AIWANBAL_DIR}/wan${_n}_state" 2>/dev/null)
-		if [ "$_mod" != "eyeride" ] && [ "$_mod" != "none" ] && [ -n "$_mod" ] && [ "$_active" = "up" ]; then
+		if [ "$_mod" != "eyeride" ] && [ "$_mod" != "none" ] && [ "$_mod" != "generic" ] && [ -n "$_mod" ] && [ "$_active" = "up" ]; then
 			echo "$_mod"; return
 		fi
 	done
@@ -415,8 +430,10 @@ _cached_speedtest() {
 	_f="${STATE_DIR}/speedtest-result-${_iface}"
 	[ -f "$_f" ] || return 1
 	_mtime=$(stat -c %Y "$_f" 2>/dev/null || stat -f %m "$_f" 2>/dev/null)
+	_mtime=$(printf '%s' "$_mtime" | tr -cd '0-9')
 	[ -n "$_mtime" ] || return 1
-	_age=$(( $(date +%s) - _mtime ))
+	_st_now=$(date +%s)
+	_age=$(( _st_now - _mtime ))
 	[ "$_age" -lt 2100 ] || return 1
 	cat "$_f"
 }