refactor: rename QoS configuration from "Default" to "Robust" and add QoS preset selection

- Rename `AuracastQosDefault` class to `AuracastQosRobust` to better reflect its characteristics (4 retransmissions)
- Replace RTN (retransmission number) dropdown with QoS preset selector offering "Fast" (2 RTN) and "Robust" (4 RTN) options
- Update frontend and backend to use QoS preset mapping instead of manual QoS config construction
- Add `_resolve_qos_preset_name()` helper function to convert QoS config

src/qualification/CAP/test_cap_ini_bst.py

@@ -10,7 +10,7 @@ Restart the stream when asked to terminate.
 import logging
 import os
 
-from auracast.auracast_config import AuracastGlobalConfig, AuracastBigConfig, AuracastQosDefault
+from auracast.auracast_config import AuracastGlobalConfig, AuracastBigConfig, AuracastQosRobust
 from auracast.multicast import broadcast, run_async
 
 
@@ -26,7 +26,7 @@ if __name__ == "__main__":
     config = AuracastGlobalConfig()
 
     # Use same QoS profile as multicast main
-    config.qos_config = AuracastQosDefault()
+    config.qos_config = AuracastQosRobust()
 
     # Transport similar to multicast main; adjust if needed for your setup
     # config.transport = "auto"  # let multicast auto-detect