Consolidates release-candidate verification: backend 420 (incl. the CI
runner's exact Ubuntu 20.04/libicu66 environment), frontend 128, all
four DB scenarios, backup/restore with a byte-exact æøå round trip,
health and auth checks.
Status: READY WITH DOCUMENTED RISKS. No open code blocker. Remaining
risks separated into code (none), infrastructure (runner instability
A/B, still unconfirmed-fixed; old runner ICU), and manual owner
verification (sign-in, production backup, production scale).
Recommendation: deploy with documented risks -- re-run CI with the ICU
fix, owner runs a real backup + scratch restore, deploy, then run the
manual smoke test.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
cesnimda