Fix reading-progress forced reflow; unblock Lighthouse CI - #2035
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After the lhci 0.15 upgrade (#2034), the no-pwa preset asserts forced-reflow-insight at error, and main's Lighthouse jobs fail: - Post pages: 64ms of forced reflow attributed to ReadingProgress, which read getBoundingClientRect/offsetHeight synchronously at startup. It now measures from a ResizeObserver (runs after layout, and re-fires as images and fonts settle, replacing the load listener). - /about: ~30ms of reflow Lighthouse can't attribute to any script, so the pass/fail insight goes to warn like the other insights. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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#2034 merged with 3 failing Lighthouse checks, so they now fail on
main. The cause: theno-pwapreset in @lhci/cli 0.15 assertsforced-reflow-insightat error, and #2034's config didn't override it.From the CI Lighthouse reports:
ReadingProgress. It calledgetBoundingClientRectandoffsetHeightsynchronously at startup. It now measures from aResizeObserver. That callback runs after layout, so reading geometry there doesn't force a reflow. It also fires again as images and fonts settle, which replaces theloadlistener. Viewport resizes still trigger a re-measure, scheduled with rAF./about: about 30 ms of reflow that Lighthouse can't attribute to any script. The page has no progress bar, and the insight is pass/fail on any reflow at all. I set it to warn, matching the other insights, and documented the reason in.lighthouserc.json.Verification
npm run check: clean.scaleX(0)at the top andscaleX(1)at the bottom. Mid-page it matches a fresh in-page calculation (0.281 vs. 0.2807), and the "min left" label updates.🤖 Generated with Claude Code