Most studios ship the build. Almost none ship the thing that catches the build failing quietly in month three. Every release here clears four gates. Two are enforced by the build pipeline and fail it outright. One is a design review scored against published thresholds. The fourth is a person who did not build the page, reading it fresh.
Five dimensions scored against a published rubric with published thresholds. A weighted score below 6.0 blocks the handoff, and so does any heavily weighted dimension below 6 — a strong average is not allowed to launder a weak spot in the thing that matters most.
Links, anchors, forms, routes and responsive behaviour down to 390px — verified by running them, not by reading the stylesheet and concluding it probably works.
Budgets are a build condition, not a post-launch audit. JavaScript ceilings per route, Core Web Vitals thresholds, and a Lighthouse floor across all four categories.
Someone who did not build the page looks at it fresh, judging composition, colour and hierarchy. Builders go blind to their own work; a cold reader does not.
External links rot. Scheduled jobs stop running without telling anyone. A run that never starts writes no log, so its absence is invisible in the record you would check. Continuing operation is a rule here, not an upsell.