Add Waterfall Chart & Request Inspector

Features Added:
- Interactive waterfall timeline visualization
- Color-coded timing bars (DNS, Connect, SSL, TTFB, Download)
- Request filtering by resource type (HTML, JS, CSS, Images, Fonts)
- Detailed request inspector dialog with timing breakdown
- HAR data extraction from Lighthouse results
- Size/compression metrics display
- Third-party resource identification
- Render-blocking resource detection

Technical Implementation:
- Created lib/har-parser.js for network data extraction
- Built waterfall.html with SVG-based timeline renderer
- Added waterfall.js with interactive controls
- Integrated HAR generation into test runner workflow
- Updated main UI with View Waterfall link

main.js

@@ -107,6 +107,16 @@ function displayResults(data) {
         </a>
     `;
     resultsArea.appendChild(actionsDiv);
+    
+    // Show waterfall link
+    const waterfallContainer = document.getElementById('waterfall-link-container');
+    if (waterfallContainer) {
+        waterfallContainer.style.display = 'block';
+        document.getElementById('view-waterfall').onclick = (e) => {
+            e.preventDefault();
+            window.open(`/waterfall.html?id=${data.id}`, '_blank');
+        };
+    }
 
     resultsArea.classList.add('visible');