Add admin invites and user workspace management tools.

Implement invite-token registration with optional email delivery, add admin UI actions for creating invites and opening user workspaces, and support superuser workspace override while preserving per-user code isolation with shared read-only lib.

Made-with: Cursor

src/static/index.html

@@ -30,6 +30,7 @@
           <span id="save-status" class="save-status"></span>
           <span class="runtime-hint" title="Python runs locally in your browser via Pyodide; completions use Jedi in the same runtime.">Browser · Pyodide</span>
           <span id="lsp-status" class="runtime-hint" title="Jedi in-browser diagnostics">LSP: n/a</span>
+          <span id="workspace-badge" class="runtime-hint hidden"></span>
         </div>
         <div class="mode-toggle">
           <a id="home-btn" class="mode-btn active" href="/">Home</a>
@@ -86,6 +87,6 @@
     </div>
   </div>
 
-  <script type="module" src="/static/script.js?v=22"></script>
+  <script type="module" src="/static/script.js?v=23"></script>
 </body>
 </html>