Modify TS Config For Route Hooks

Updates the web/tsconfig.json file to include a path alias for $api.

This allows you to import for example

import { db } from '$api/src/lib/db'
import { bazinga } from '$api/src/lib/bazinga'

Just like in scripts, in your *.routeHooks.ts files. This feature was enabled as part of Cell prerendering and dynamic path prerendering.