v0.3.0b4

Prerelease with storage and active BLE stability fixes.\n\nChanges:\n- Removed recorder-backed diagnostic sensor platform to avoid Home Assistant database growth.\n- Kept Aruba APs as Home Assistant Bluetooth scanner sources.\n- Moved CLI generation work off the event loop.\n- Added configurable active BLE connection slots, with conservative default of 1 per AP.\n- Kept active BLE operations serialized per Aruba AP for stability after Aruba returned invalid-state errors during parallel connects.\n- Updated docs and field test templates for sensor-free validation.\n\nValidation:\n- 166 pytest tests passing.\n- Privacy scan clean for known local MAC/IP/token values.