fix(perf): bench jq direction bug + libaio + json note guard [#709]

- write tests read .write.* explicitly (jq // kept read=0 for writes)
- libaio1 installed everywhere (real aio engine, no sync cap)
- fio stdout notes stripped before jq parse

Ticket: https://projects.knownelement.com/issues/709

proxmox/perf/bench/install-bench.sh

@@ -5,5 +5,5 @@
 set -eu
 export DEBIAN_FRONTEND=noninteractive
 apt-get update -qq
-apt-get install -y -qq fio iperf3 jq >/dev/null
+apt-get install -y -qq fio iperf3 jq libaio1 >/dev/null
 echo "bench toolset installed: fio=$(fio --version 2>/dev/null | awk '{print $3}') iperf3=$(iperf3 --version 2>/dev/null | awk 'NR==1{print $2}')"