refactor: Rename "gpt-4o-realtime" to "gpt-realtime" in RealtimeModelName type alias

Author: oristides

src/agents/realtime/config.py

@@ -15,7 +15,7 @@
 
 RealtimeModelName: TypeAlias = Union[
     Literal[
-        "gpt-4o-realtime",
+        "gpt-realtime",
         "gpt-4o-realtime-preview",
         "gpt-4o-mini-realtime-preview",
         "gpt-4o-realtime-preview-2025-06-03",