Make a slow page fast by measuring first

Claude Code measures the slow page, fixes the real bottleneck and measures again, with Addy Osmani's performance skill. Then plain code checks it: fewer queries, the same output, tests green, nothing else touched.

Our run, 2026-10-03. Plain code checked Claude's fix: 401 queries per page became 1, the median time fell from 6.07 to 1.41 ms (4.3x), the page is byte for byte the same, all 8 tests pass and the daily report was left alone.