fix(renderer): give the chrome_proxy recovery arm time to finish - #510
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The arm ran with a 12 s budget while a residential Chrome render of a page behind Azure Front Door measures 12.3 to 16.3 s end to end (www.carfax.ca, 2026-09-08). The arm therefore timed out on 9 of 11 attempts and the caller got the direct tier's 403 shell, although the same page cleared 6 of 6 times when chrome_proxy was pinned with a larger budget. CHROME_PROXY_ARM_BUDGET_MS is 20 s, and the chrome_proxy tier's nav budget is raised to at least that, since the effective render budget is the smaller of the two. The direct chrome tier keeps chrome_nav_budget_ms, so the hot path is unchanged; only hard-blocked requests, which already failed the ladder, pay the extra time.
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What changed
CHROME_PROXY_ARM_BUDGET_MS12 s to 20 s incrates/crw-renderer/src/lib.rs.chrome_proxytier's navigation budget ischrome_nav_budget_ms.max(CHROME_PROXY_ARM_BUDGET_MS), since the effective render budget is the smaller of the two. The directchrometier keepschrome_nav_budget_ms.Why
Measured 2026-09-08 against
www.carfax.ca(Azure Front Door 403 on every datacenter IP): the engine already classifies the page as a hard block and fires the residential recovery arm, but a residential Chrome render of that page takes 12.3 to 16.3 s end to end. With a 12 s arm the auto path succeeded on 2 of 11 attempts; withchrome_proxypinned and a larger budget it succeeded 6 of 6 (7.7k characters of real markdown).Effect
timeoutbelow that returns 504 as before.chrome_proxypool permits are held up to 20 s instead of 12 s on those requests. Watchrender_route_decision_total{tier="chromeProxy",decision="armShed"}after deploy.ref #189