feat(web): improve /auth pages (#1969)

* feat(web): improve /auth pages

* invalidate load functions after login

* handle login server errors more graceful

* add loading state to oauth button

web/src/routes/auth/login/+page.server.ts

@@ -1,14 +1,32 @@
+import { AppRoute } from '$lib/constants';
 import { redirect } from '@sveltejs/kit';
+import type { OAuthConfigResponseDto } from '@api';
 import type { PageServerLoad } from './$types';
 
 export const load = (async ({ locals: { api } }) => {
 	const { data } = await api.userApi.getUserCount(true);
 	if (data.userCount === 0) {
 		// Admin not registered
-		throw redirect(302, '/auth/register');
+		throw redirect(302, AppRoute.AUTH_REGISTER);
+	}
+
+	let authConfig: OAuthConfigResponseDto = {
+		passwordLoginEnabled: true,
+		enabled: false
+	};
+
+	try {
+		// TODO: Figure out how to get correct redirect URI server-side.
+		const { data } = await api.oauthApi.generateConfig({ redirectUri: '/' });
+		data.url = undefined;
+
+		authConfig = data;
+	} catch (err) {
+		console.error('[ERROR] login/+page.server.ts:', err);
 	}
 
 	return {
+		authConfig,
 		meta: {
 			title: 'Login'
 		}