Create evlog Framework Integration

Add a new framework integration to evlog. The recommended path is the manifest mode built on defineFrameworkIntegration from evlog/toolkit, for any framework with a request/response middleware shape. For frameworks with a fundamentally different lifecycle you'll fall back to the lower-level createMiddlewareLogger.

Two paths

• Manifest mode (preferred, ~30–80 lines of glue). Call defineFrameworkIntegration({ name, extractRequest, attachLogger, storage? }) once at module level, then write a tiny middleware that calls integration.start(ctx, options) and runs the framework's next() inside runWith. Reference implementations: all of packages/evlog/src/{hono,express,fastify,elysia,nestjs,orpc,react-router,sveltekit,workers}/index.ts use it.
• Custom mode: use createMiddlewareLogger directly when the framework's lifecycle doesn't fit a standard middleware. Current custom-mode integrations: Next.js (src/next/), Nitro v2/v3 (src/nitro/, src/nitro-v3/), Eve (src/eve/).

Manifest mode now covers all classic HTTP frameworks. Use custom mode only when you can't extract a request synchronously at the start of the lifecycle (server actions, module-level hooks, agent turns).

Required API surface (from AGENTS.md)

Every framework integration must expose:

1. evlog() middleware/plugin accepting the full BaseEvlogOptions (drain, enrich, keep, include, exclude, routes, plugins)
2. useLogger() (ALS-backed). Workers is the one sanctioned exception (ALS needs a compat flag there; defineWorkerFetch attaches the logger instead)
3. log.fork() support (automatic when storage is provided to the manifest)
4. The framework-native accessor (c.get('log'), req.log, event.locals.log, …)