Add a way to access available param-matchers from inside a library

Describe the problem

It's currently not possible to access the param-matcher-functions that are available in an App from inside a library. They need to be passed into the library by reference, one-by-one.

I have a library that requires access to the matcher-functions as it operates on routeIDs.

• Having to pass matchers to the library one-by-one is cumbersome and error-prone since you're likely to forget to add new matchers
• vite-glob-imports don't work since they don't respect kit.files.params

As discussed in: https://discord.com/channels/457912077277855764/1226858732223205497/1226858732223205497

Describe the proposed solution

A way to access the matcher-functions that are present in an app. For example an $app/matchers module where we can import the matcher functions from. Given that matchers are already shipped to the client this wouldn't make a meaningful bundle-size difference, it's just about exposing them.

Example:

import * as matchers from "$app/matchers"

matchers.int("123") // true
matchers.float("asd") //false

const availableMatchers = Object.keys(matchers) // ["int", "float", "uuid"]

Alternatives considered

Require library users to pass in matcher-functions one by one. This is awkward since they'er all exported as "match" and the matcher name is implicit from the filename.

import { init } from "some-library"
import { match as int } from "../params/int.js"
import { match as float } from "../params/float.js"

init({ matchers: { int, float }})

Importance

nice to have

Additional Information

No response

Start by tracing how matcher functions from kit.files.params are loaded and shipped to the client, and how libraries handle routeIDs. Compare the proposed $app/matchers module with the one-by-one imports from ../params/*. Done means a library can enumerate and call all matchers available in the app without manual wiring.