Add the Next.js web app and shared lesson content.

Move lessons out of the C sources into JSON so the web client can use the same material as the desktop app, and point release builds at desktop/.

Co-authored-by: Cursor <cursoragent@cursor.com>

web/src/app/networks/year-1/[lesson]/page.tsx

@@ -0,0 +1,23 @@
+import { notFound } from 'next/navigation';
+
+import { getLesson, getLessonIds } from '@/content';
+import { LessonScreen } from '@/components/LessonScreen';
+
+export async function generateStaticParams() {
+  const ids = await getLessonIds('networks');
+  return ids.map((lesson) => ({ lesson }));
+}
+
+export default async function NetworkLessonPage({
+  params,
+}: {
+  params: Promise<{ lesson: string }>;
+}) {
+  const { lesson: id } = await params;
+
+  try {
+    return <LessonScreen lesson={await getLesson('networks', id)} backHref="/networks/year-1" />;
+  } catch {
+    notFound();
+  }
+}