feat: implement VAD agent

Listens to audio from the RI, does voice activity detection, sends voice fragments.

ref: N25B-213

src/control_backend/core/config.py

@@ -2,14 +2,20 @@ from re import L
 from pydantic import BaseModel
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
+
 class ZMQSettings(BaseModel):
     internal_comm_address: str = "tcp://localhost:5560"
 
+    audio_fragment_port: int = 5561
+    audio_fragment_address: str = f"tcp://localhost:{audio_fragment_port}"
+
+
 class AgentSettings(BaseModel):
     host: str = "localhost"
     bdi_core_agent_name: str = "bdi_core"
     belief_collector_agent_name: str = "belief_collector"
-    test_agent_name: str = "test_agent"
+    vad_agent_name: str = "vad_agent"
+
 
 class Settings(BaseSettings):
     app_title: str = "PepperPlus"
@@ -21,5 +27,6 @@ class Settings(BaseSettings):
     agent_settings: AgentSettings = AgentSettings()
     
     model_config = SettingsConfigDict(env_file=".env")
-    
+
+
 settings = Settings()