Fix device card rendering - disable legacy code and fix CSS

- Disable legacy addBtDeviceCard when BluetoothMode is active
- Clear device container when starting scan to remove legacy cards
- Fix grid CSS with explicit auto height and align-items: start
- Add visibility rules for all card body elements
- Reset devices map when clearing container

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

templates/index.html

@@ -6315,6 +6315,11 @@
 
         // Add Bluetooth device card to device list panel
         function addBtDeviceCard(device, isNew) {
+            // Skip if new BluetoothMode is handling rendering
+            if (typeof BluetoothMode !== 'undefined' && BluetoothMode.isScanning()) {
+                return;
+            }
+
             // Add to new device list panel
             const deviceList = document.getElementById('btDeviceListContent');
             if (deviceList) {