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/package.json

@@ -0,0 +1,24 @@
+{
+  "name": "maturita-web",
+  "version": "1.0.0",
+  "private": true,
+  "scripts": {
+    "dev": "next dev",
+    "build": "next build",
+    "start": "next start",
+    "lint": "next lint",
+    "typecheck": "tsc --noEmit",
+    "content": "node ../tools/build-content.mjs"
+  },
+  "dependencies": {
+    "next": "^16.3.5",
+    "react": "^19.1.1",
+    "react-dom": "^19.1.1"
+  },
+  "devDependencies": {
+    "@types/node": "^22.10.2",
+    "@types/react": "^19.1.8",
+    "@types/react-dom": "^19.1.6",
+    "typescript": "^5.7.2"
+  }
+}