Adds a 'Requests' tab to the debug panel (Ctrl/Cmd+Shift+D) that wraps
window.fetch while the panel is open to track every request as in-flight
from call to promise settle, sampled once per second over a 5-minute
rolling window.
Charts:
- in-flight request count over time (current + peak)
- p50/p90/p99/max age distribution of currently in-flight requests,
with the legend below the chart and a y-axis max label for scale
Tracking is fully gated behind the panel: closing it stops the sampling
interval, unwraps window.fetch, and drops all state (zero overhead when
not debugging). i18n keys added to all 9 locales.
Tom Rochette
ecc70fa15d