Review-bot flagged Caddyfile.tradein-fragment as shared gendsgn.ru gateway
infra needing devops review. The app-level asyncio.wait_for budgets already
bound the slow enrichment chain, so the 502 fix stands without the gateway
timeout. Caddy read/write timeout to be applied separately under devops review.
POST /estimate returned an opaque 502 (gateway timeout), not a null-floor
crash: the ungated Yandex valuation (30s httpx) + geocode/Overpass chain run
serially on every estimate. Wraps slow enrichments in asyncio.wait_for budgets
(config) so a slow upstream degrades to None instead of exceeding the gateway
read timeout. Handler try/except -> logger.exception + 503 so future real
errors are visible (GlitchTip) not masked. Explicit Caddy read/write timeout.
Tests: null-floor skips IMV/Cian (no 5xx); Yandex timeout degrades. 65 regr pass.
NOTE: Caddyfile.tradein-fragment is shared infra — devops review required.
Closes#654