Update cluster tokens page to match API tokens flow with modals and copy functionality

vidai/web.py

@@ -436,8 +436,11 @@ def generate_cluster_token():
 
     from .auth import generate_worker_token
     token = generate_worker_token(token_name)
-    flash(f'New cluster token "{token_name}" generated: {token[:20]}...', 'success')
-    return redirect(url_for('cluster_tokens'))
+    # Return with modal data instead of flash
+    from .database import get_worker_tokens
+    worker_tokens = get_worker_tokens()
+    user = get_current_user_session()
+    return render_template('admin/cluster_tokens.html', user=user, worker_tokens=worker_tokens, generated_token=token, token_name=token_name, show_modal=True, active_page='cluster_tokens')
 
 @app.route('/admin/cluster_tokens/<int:token_id>/deactivate', methods=['POST'])
 @admin_required