fix(dashboard): add cache-busting and defensive chartManager guards to fix empty charts

static/js/pages/monitoring.js

@@ -153,6 +153,13 @@ class MonitoringPage {
     }
 
     async loadCharts() {
+        // Ensure chartManager is available
+        const cm = window.chartManager || await window.waitForChartManager();
+        if (!cm) {
+            console.warn('chartManager unavailable, skipping monitoring charts');
+            return;
+        }
+
         // Fetch recent logs for chart data
         try {
             const logs = await window.api.get('/system/logs');
@@ -168,6 +175,8 @@ class MonitoringPage {
 
     async loadResponseTimeChart() {
         try {
+            const cm = window.chartManager;
+            if (!cm) return;
             // Bucket recent logs by minute for latency chart
             const buckets = this.bucketByMinute(this.recentLogs, 20);
             const labels = buckets.map(b => b.label);
@@ -187,7 +196,7 @@ class MonitoringPage {
                 }]
             };
 
-            window.chartManager.createLineChart('response-time-chart', data, {
+            cm.createLineChart('response-time-chart', data, {
                 scales: {
                     y: {
                         title: { display: true, text: 'Milliseconds' },
@@ -202,6 +211,8 @@ class MonitoringPage {
 
     async loadErrorRateChart() {
         try {
+            const cm = window.chartManager;
+            if (!cm) return;
             const buckets = this.bucketByMinute(this.recentLogs, 20);
             const labels = buckets.map(b => b.label);
             const values = buckets.map(b => {
@@ -220,7 +231,7 @@ class MonitoringPage {
                 }]
             };
 
-            window.chartManager.createLineChart('error-rate-chart', data, {
+            cm.createLineChart('error-rate-chart', data, {
                 scales: {
                     y: {
                         title: { display: true, text: 'Percentage' },
@@ -238,6 +249,8 @@ class MonitoringPage {
 
     async loadRateLimitChart() {
         try {
+            const cm = window.chartManager;
+            if (!cm) return;
             // Show requests-per-client from recent logs
             const clientCounts = {};
             for (const log of this.recentLogs) {
@@ -257,7 +270,7 @@ class MonitoringPage {
                 }]
             };
 
-            window.chartManager.createBarChart('rate-limit-chart', data, {
+            cm.createBarChart('rate-limit-chart', data, {
                 scales: {
                     y: {
                         title: { display: true, text: 'Request Count' },
@@ -452,22 +465,24 @@ class MonitoringPage {
     }
 
     updateCharts(metric) {
+        const cm = window.chartManager;
+        if (!cm) return;
         // Update charts with new metric data
-        if (metric.type === 'response_time' && window.chartManager.charts.has('response-time-chart')) {
+        if (metric.type === 'response_time' && cm.charts.has('response-time-chart')) {
             this.updateResponseTimeChart(metric.value);
         }
         
-        if (metric.type === 'error_rate' && window.chartManager.charts.has('error-rate-chart')) {
+        if (metric.type === 'error_rate' && cm.charts.has('error-rate-chart')) {
             this.updateErrorRateChart(metric.value);
         }
     }
 
     updateResponseTimeChart(value) {
-        window.chartManager.addDataPoint('response-time-chart', value);
+        if (window.chartManager) window.chartManager.addDataPoint('response-time-chart', value);
     }
 
     updateErrorRateChart(value) {
-        window.chartManager.addDataPoint('error-rate-chart', value);
+        if (window.chartManager) window.chartManager.addDataPoint('error-rate-chart', value);
     }
 
     startDemoUpdates() {