Investigate production Texture API 5xx bursts on 2026-07-30

Requested by Slava from Datadog monitor event 1785403306. Investigate texture-api HTTP 5xx bursts (including 281 errors / 5m around 08:16 UTC and 7 errors / 5m around 09:21 UTC): determine affected paths, error signatures, dependencies, deploy correlation, impact, and remediation. Read-only investigation only; no production mutations.