Add local authentication option (#37)

Co-authored-by: Shaun Campbell <shaun@campbellwireless.net>
Reviewed-on: #37
Co-authored-by: AI Agent <ai-agent@campbellwireless.net>
Co-committed-by: AI Agent <ai-agent@campbellwireless.net>

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

@@ -1,8 +1,20 @@
 import { env } from '$env/dynamic/private';
 import type { PageServerLoad } from './$types';
 
-export const load: PageServerLoad = async () => {
+const resolveErrorMessage = (value: string | null): string | null => {
+	if (!value) return null;
+	if (value === 'CredentialsSignin') return 'Invalid credentials';
+	return null;
+};
+
+export const load: PageServerLoad = async ({ url }) => {
+	const authUrl = process.env.AUTH_URL ?? env.AUTH_URL ?? '';
+	const localAuthEnabled = (process.env.LOCAL_AUTH_ENABLED ?? env.LOCAL_AUTH_ENABLED) === 'true';
+
 	return {
-		signinUrl: `${env.AUTH_URL}/signin/synology`
+		signinUrl: `${authUrl}/signin/synology`,
+		localSigninUrl: `${authUrl}/signin/local`,
+		localAuthEnabled,
+		error: resolveErrorMessage(url.searchParams.get('error'))
 	};
 };