Add tutorial route; gate lib workspace for superusers; Py worker v4

- Serve /tutorial and add tutorial.html/tutorial.js assets
- Fetch auth role; hide lib from non-superusers in tree and restored tabs
- Cache workspace Python sources briefly for Py worker
- Pyodide worker and home/index links/styling tweaks

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

src/editor_app/routers/frontend.py

@@ -16,6 +16,11 @@ async def serve_frontend():
     return FileResponse(STATIC_DIR / "index.html")
 
 
+@router.get("/tutorial")
+async def serve_tutorial():
+    return FileResponse(STATIC_DIR / "tutorial.html")
+
+
 @router.get("/login")
 async def serve_login():
     return FileResponse(STATIC_DIR / "login.html")