Updated lint errors and lint fix

src/app.js

@@ -111,7 +111,7 @@ app.get('/', (req, res) => {
 });
 
 // Error handler
-app.use((err, req, res, next) => {
+app.use((err, req, res, _next) => {
   console.error('💥 Error:', err);
   res.status(500).json({ error: err.message });
 });

src/public/app.js

@@ -220,7 +220,7 @@ class MonitoringDashboard {
     const container = document.getElementById('api-metrics');
 
     const requestCounters = data.counters.filter(c => c.name === 'http_requests_total');
-    const responseCounters = data.counters.filter(c => c.name === 'http_responses_total');
+    // const _responseCounters = data.counters.filter(c => c.name === 'http_responses_total');
     const durationHistograms = data.histograms.filter(h => h.name === 'http_request_duration_ms');
 
     let html = '<div class="metrics-grid">';
@@ -303,7 +303,7 @@ class MonitoringDashboard {
 
   updateStatus(status, text) {
     const indicator = document.getElementById('status-indicator');
-    const dot = document.getElementById('status-dot');
+    // const _dot = document.getElementById('status-dot');
     const statusText = document.getElementById('status-text');
 
     indicator.className = `status-indicator ${status}`;
@@ -367,6 +367,7 @@ class MonitoringDashboard {
 }
 
 // Global functions for buttons
+// eslint-disable-next-line no-unused-vars
 async function refreshData() {
   const dashboard = window.dashboard;
   if (dashboard) {
@@ -374,6 +375,7 @@ async function refreshData() {
   }
 }
 
+// eslint-disable-next-line no-unused-vars
 async function testAPI() {
   try {
     const response = await fetch('/api/test');
@@ -392,6 +394,7 @@ async function testAPI() {
   }
 }
 
+// eslint-disable-next-line no-unused-vars
 async function downloadMetrics() {
   try {
     const response = await fetch('/api/metrics');