chore: clear the mechanical lint and type findings

Dead imports and locals removed, each blocks keyed, `any` narrowed to unknown.
Two context setters kept their calls and lost only the unused binding; the
settings redirect no longer awaits a parent whose data it discards. A leading
underscore now marks a binding that only holds a position.

frontend/src/lib/api/auth.remote.ts

@@ -4,7 +4,7 @@ import { BACKEND_API_URL } from '$lib/server/config';
 import { invalid, redirect } from '@sveltejs/kit';
 
 export const login = form(loginSchema, async (data, issue) => {
-	const { cookies, locals } = getRequestEvent();
+	const { cookies } = getRequestEvent();
 
 	// Create URL-encoded form data
 	const formData = new URLSearchParams();