Implement BLE device discovery

docs/host_dri_rebuild.md

@@ -43,7 +43,26 @@ Implemented behavior:
 - stay transport-only
 - keep real BLE implementation for a later node
 
-### Node 2: CDC transport cleanup
+### Node 2: BLE device discovery
+
+Files updated in this step:
+
+- `KeyBorad/KeyBorad/DRI/GATT/Dri_Gatt.cpp`
+- `KeyBorad/KeyBorad/KeyBorad.vcxproj`
+
+Design notes:
+
+- use Qt Bluetooth directly
+- keep discovery synchronous for now so the first teaching step stays small
+- only collect low-energy devices
+
+Implemented behavior:
+
+- start BLE discovery with `QBluetoothDeviceDiscoveryAgent`
+- collect device name and address
+- filter to `LowEnergyCoreConfiguration`
+- stop after a short timeout
+### Node 3: CDC transport cleanup
 
 Files updated in this step: