disable study_templates feature — no backend to serve them

TradingView's SaveloadAdapter.Library was making HTTP requests for study
templates that returned HTML from nginx, causing JSON parse errors that
destroyed the datafeed and disconnected the WebSocket.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/src/components/ChartView.vue

@@ -48,7 +48,7 @@ onMounted(() => {
           'header_symbol_search',
           'symbol_search_hot_key'
         ],
-        enabled_features: ['study_templates'],
+        enabled_features: [],
         // Restrict indicators to only those supported by both TA-Lib and TradingView
         studies_access: {
           type: 'white',