Samples /proc/PID/stat directly (no pidstat dependency) for the qbz binary
and any WebKit child processes. Outputs mean/p50/p95/max per process plus
appends a CSV row to /tmp/qbz-cpu-measurements.csv for cross-run comparison.
Usage:
./scripts/measure-cpu-window.sh <label> [duration_seconds]
Built during the 2026-05-11 perf debug session to replace seat-of-the-pants
"does it feel faster?" with comparable numbers across changes.
cc
