Introducing deeper integrations for feature flags in Vercel

What this post added

This post introduces deeper integrations for feature flags within Vercel's Developer Experience Platform. Key contributions include: 1. Overriding feature flags directly from the Vercel Toolbar via an API Route and DOM scanning, with overrides stored in encrypted cookies. 2. Integration with Vercel Web Analytics and Runtime Logs to filter and break down data by feature flags, providing context for debugging and analysis. 3. A "feature flags as code" design pattern using `@vercel/flags/next` and `@vercel/flags/react` to enable server-side experimentation and precompute flag values for routing decisions in Middleware, aiming to eliminate client-side "jank".