Allow type augmentation for Request.context

[kling90]

The current inline type definition can't be augmented via TypeScript module augmentation. This change makes it possible to add type-safe properties to req.context when passing data from hooks to routes.

By extracting to a named Context interface you can now augment it:

import type { User } from './api/findUser';

declare module '@sitevision/api/common/router' {
  interface Context {
    user: User;
  }
}

In hooks.ts

hooks.beforeRender((req, res) => { 
  const user = findUser();
  req.context.user = user;
});

In index.ts

router.get('/', (req, res) => {
  const { user } = req.context;
});

Should the Session be an interface as well to make augmentation possible?

I made a PR for this suggestions since I guessed this isn't part of the definitions that get generated from JavaDoc?