fix(frontend): add clearDriveSelection() function for undoing drive selection

- Add clearDriveSelection() to reset UI state and uncheck radio buttons
- Show clear selection button when drive is selected
- Fixes issue #1: undo disk selection

static/js/main.js

@@ -132,6 +132,12 @@ function selectDrive(drive) {
         `;
     }
     
+    // Show clear selection button
+    const clearContainer = document.getElementById('clear-selection-container');
+    if (clearContainer) {
+        clearContainer.style.display = 'block';
+    }
+    
     // Enable benchmark configuration section
     const configDiv = document.getElementById('benchmark-config');
     if (configDiv) {
@@ -143,6 +149,44 @@ function selectDrive(drive) {
     }
 }
 
+// Handle drive deselection (clear selection)
+function clearDriveSelection() {
+    selectedDrive = null;
+    console.log('Cleared drive selection');
+    
+    // Clear selected drive info
+    const infoDiv = document.getElementById('selected-drive-info');
+    if (infoDiv) {
+        infoDiv.innerHTML = '';
+    }
+    
+    // Hide clear selection button
+    const clearContainer = document.getElementById('clear-selection-container');
+    if (clearContainer) {
+        clearContainer.style.display = 'none';
+    }
+    
+    // Disable benchmark configuration section
+    const configDiv = document.getElementById('benchmark-config');
+    if (configDiv) {
+        configDiv.classList.add('opacity-50');
+        configDiv.querySelector('.card-body').innerHTML = `
+            <p class="text-muted">Select a drive above to configure benchmark parameters.</p>
+        `;
+    }
+    
+    // Uncheck all radio buttons
+    const radios = document.querySelectorAll('input[name="selected_drive"]');
+    radios.forEach(radio => { radio.checked = false; });
+}
+
+// Listen for clear selection button click
+document.addEventListener('click', function(evt) {
+    if (evt.target.id === 'clear-selection-btn' || evt.target.closest('#clear-selection-btn')) {
+        clearDriveSelection();
+    }
+});
+
 // Listen for HTMX events
 document.addEventListener('htmx:afterRequest', function(evt) {
     // Render drives in home page