Add input validation

[Nydauron]

No endpoints that take in the HTTP body, params, or query use any form of runtime validation. as is not good enough (frankly not good at all) in these scenarios because that only provides a static check and is never used during runtime when dealing with incoming requests. I would suggest using something like zod-express-middleware with zod to easily couple an input schema for each route that needs it. Resulting malformed requests then will return back a 400 status code instead of 500.

Example:

router.get(
    "/:USERID/",
    validateRequestParams(
        z.object({
            USERID: z.string().min(1),
        }),
    ),
    async (req, res, next) => {
        const userId = req.params.USERID;
        //      ^?     string
        // ...
    }
);