fix: use ingest HTTP API instead of direct Postgres for VPS telemetry; cache speedtest results per interface

- hub/server.py: replace psycopg2 Postgres connection with urllib HTTP call to
  ingest /api/devices endpoint (fleet Postgres is Docker-internal, not reachable
  from the VPS directly)
- telemetry-synology.sh: run_speedtest() now writes per-interface cache files
  (speedtest-result-<iface>); _cached_speedtest() reads cache if < 35 min old;
  _collect_wan() uses cached result so throughput shows in telemetry without
  blocking every 1-min cycle

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

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

@@ -286,8 +286,14 @@ _collect_wan() {
 		_jitter=$(echo "$_ping_result" | awk '{print $2}')
 		_loss=$(echo "$_ping_result" | awk '{print $3}')
 		_score=$(_compute_score "$_lat" "$_loss")
-		_dl="0.0"
-		_ul="0.0"
+		# Use cached speedtest result if available and fresh
+		_st=$(_cached_speedtest "$_iface" 2>/dev/null)
+		if [ -n "$_st" ]; then
+			_dl=$(echo "$_st" | awk '{print $1}')
+			_ul=$(echo "$_st" | awk '{print $2}')
+		fi
+		[ -z "$_dl" ] || [ "$_dl" = "0" ] && _dl="0.0"
+		[ -z "$_ul" ] || [ "$_ul" = "0" ] && _ul="0.0"
 	fi
 
 	printf '{"score":%s,"latency_ms":%s,"dl_mbps":%s,"ul_mbps":%s,"jitter_ms":%s,"loss_pct":%s}' \
@@ -364,10 +370,10 @@ _eyeride_signal() {
 }
 
 # ── Speedtest ──────────────────────────────────────────────────────────────
-# Run a speedtest bound to a specific interface. Reports dl_mbps ul_mbps.
+# Run a speedtest bound to a specific interface. Caches result per-interface.
 run_speedtest() {
 	_iface="$1"
-	_result="0 0"
+	_result_file="${STATE_DIR}/speedtest-result-${_iface}"
 	# Try speedtest-cli first
 	if which speedtest-cli >/dev/null 2>&1; then
 		_out=$(speedtest-cli --interface "$_iface" --json 2>/dev/null)
@@ -377,27 +383,16 @@ run_speedtest() {
 			if [ -n "$_dl" ] && [ -n "$_ul" ]; then
 				_dl_mbps=$(awk "BEGIN { printf \"%.1f\", ${_dl} / 125000 }" 2>/dev/null)
 				_ul_mbps=$(awk "BEGIN { printf \"%.1f\", ${_ul} / 125000 }" 2>/dev/null)
+				printf '%s %s\n' "${_dl_mbps}" "${_ul_mbps}" > "$_result_file"
 				echo "${_dl_mbps} ${_ul_mbps}"
 				return 0
 			fi
 		fi
 	fi
-	# Fallback: iperf3 single-stream test to public server
-	if which iperf3 >/dev/null 2>&1; then
-		_out=$(timeout 15 iperf3 -B "$_ip" -c iperf.he.net -p 5201 -J 2>/dev/null)
-		if [ -n "$_out" ]; then
-			_dl=$(_json_get_num "$_out" "bits_per_second")
-			if [ -n "$_dl" ]; then
-				_dl_mbps=$(awk "BEGIN { printf \"%.1f\", ${_dl} / 1000000 }" 2>/dev/null)
-				echo "${_dl_mbps} 0"
-				return 0
-			fi
-		fi
-	fi
 	# Fallback: curl a known file and measure throughput
 	_tmp="/tmp/speedtest-$$"
 	_start=$(date +%s)
-	if curl -s --interface "$_iface" --max-time 10 -o "$_tmp" http://speedtest.tele2.net/1MB.zip 2>/dev/null; then
+	if curl -s --interface "$_iface" --max-time 15 -o "$_tmp" http://speedtest.tele2.net/10MB.zip 2>/dev/null; then
 		_end=$(date +%s)
 		_bytes=$(wc -c < "$_tmp" 2>/dev/null)
 		rm -f "$_tmp"
@@ -405,6 +400,7 @@ run_speedtest() {
 			_duration=$(( _end - _start ))
 			[ "$_duration" -lt 1 ] && _duration=1
 			_dl_mbps=$(awk "BEGIN { printf \"%.1f\", ${_bytes} * 8 / ${_duration} / 1000000 }" 2>/dev/null)
+			printf '%s 0\n' "${_dl_mbps:-0}" > "$_result_file"
 			echo "${_dl_mbps:-0} 0"
 			return 0
 		fi
@@ -413,6 +409,18 @@ run_speedtest() {
 	echo "0 0"
 }
 
+# Read cached speedtest result for an interface if < 35 minutes old.
+_cached_speedtest() {
+	_iface="$1"
+	_f="${STATE_DIR}/speedtest-result-${_iface}"
+	[ -f "$_f" ] || return 1
+	_mtime=$(stat -c %Y "$_f" 2>/dev/null || stat -f %m "$_f" 2>/dev/null)
+	[ -n "$_mtime" ] || return 1
+	_age=$(( $(date +%s) - _mtime ))
+	[ "$_age" -lt 2100 ] || return 1
+	cat "$_f"
+}
+
 # ── Telemetry Collection ───────────────────────────────────────────────────
 telemetry_collect() {
 	now=$(date +%s)