Makes dynamic configuration work in production

If a static file is mounted in the Docker image, it will be read at
each page load and sent to the client.

src/routes/+page.server.ts

@@ -0,0 +1,20 @@
+import { dev } from '$app/environment';
+import { config, type Config } from '$lib/config';
+import type { PageServerLoad } from './$types';
+
+import { readFileSync } from 'fs';
+import * as yml from 'js-yaml';
+
+export const load: PageServerLoad = () => {
+	if (dev) {
+		return { config: config };
+	}
+
+	try {
+		const dynamic = yml.load(readFileSync('/dynamic/config.yml', 'utf8'));
+		return { config: { ...config, ...dynamic } as Config };
+	} catch (err) {
+		console.debug("could not read '/dynamic/config.yml': " + err);
+		return { config: config };
+	}
+};