Add missing global variables: indicatorPanes and nextPaneIndex

These variables were used in drawIndicatorsOnChart but never declared at module level.
Added declarations to fix 'indicatorPanes is not defined' error.

src/api/dashboard/static/js/ui/indicators-panel-new.js

@@ -7,6 +7,10 @@ let searchQuery = '';
 let selectedCategory = 'all';
 let nextInstanceId = 1;
 
+// Chart pane management
+let indicatorPanes = new Map();
+let nextPaneIndex = 1;
+
 // Presets storage
 let userPresets = JSON.parse(localStorage.getItem('indicator_presets') || '{}');