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>

.gitignore

@@ -18,6 +18,19 @@ build/
 
 # Generated from assets/app-icon.png (Makefile / CMake POST_BUILD)
 assets/icons/
+desktop/assets/icons/
+desktop/maturita
+
+# ---> Node / Next.js (web/)
+node_modules/
+.next/
+out/
+.turbo/
+*.tsbuildinfo
+.env*.local
+.vercel
+# Generated by `next dev` for AI agents (same reason CLAUDE.md is ignored above)
+web/AGENTS.md
 
 # Object files
 *.o