Sub-ticket of PLUTO-170 FUTURE (recommend, separate from skew fast-follow): enable next.config deploymentId + Vercel Skew Protection (if Pluto's plan allows) for a SOUND client-vs-server build compare — gives the app a real origin-build signal (today the build-ID is COARSE: app sees only its own serving build, never the client's origin build, which is why an app-side skew downgrade is unsound and the daemon owns the deploy-timing discriminator). Also makes a real end-to-end deploy-skew test possible. Low pri. · pluto