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/next.config.ts

@@ -0,0 +1,10 @@
+import type { NextConfig } from 'next';
+
+const config: NextConfig = {
+  // `content/` lives outside web/, so allow tracing files from the repo root.
+  outputFileTracingRoot: __dirname + '/..',
+  // Routes are built from content ids at runtime, so they cannot be statically typed.
+  typedRoutes: false,
+};
+
+export default config;