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/static/styles.css

@@ -245,6 +245,7 @@ body {
   overflow: hidden;
 }
 
+
 .hidden {
   display: none !important;
 }