feat: BusyBox-compatible telemetry script for Synology

Uses sed instead of grep -P for BusyBox ash compatibility.
Writes JSON to temp file to avoid shell escaping issues.
Posts to fleet hub ingest at 167.172.237.162:8080.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/telemetry-synology-simple.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+# Busrouter telemetry — BusyBox-compatible. Posts device state to fleet hub.
+HUB="http://167.172.237.162:8080/api/telemetry"
+ID=$(cat /etc/busrouter/device-id 2>/dev/null || hostname)
+TS=$(date +%s)
+UP=$(awk '{printf "%d", $1}' /proc/uptime 2>/dev/null)
+
+# BusyBox grep doesn't have -P; use sed instead
+WAN1=$(ip -4 addr show eth0 2>/dev/null | sed -n 's/.*inet \([0-9.]*\).*/\1/p' | head -1)
+WAN2=$(ip -4 addr show eth2 2>/dev/null | sed -n 's/.*inet \([0-9.]*\).*/\1/p' | head -1)
+GW=$(ip route show default 2>/dev/null | sed -n 's/.*via \([0-9.]*\).*/\1/p' | head -1)
+
+# Build JSON with proper escaping for BusyBox
+cat >/tmp/telemetry.json <<EOF
+{"device_id":"$ID","platform":"synology","timestamp":$TS,"uptime":$UP,"version":"0.1-0001","wan":{"wan1":{"ip":"$WAN1"},"wan2":{"ip":"$WAN2"},"gateway":"$GW"}}
+EOF
+
+curl -s --connect-timeout 5 --max-time 10 -X POST "$HUB" \
+  -H "Content-Type: application/json" \
+  -d @/tmp/telemetry.json >/dev/null 2>&1
+rm -f /tmp/telemetry.json