feat: (hopefully) face detection

Simplified implementation, relying on the already-present VED Agent.

ref: N25B-395

src/control_backend/agents/bdi/agentspeak_generator.py

@@ -30,6 +30,7 @@ from control_backend.schemas.program import (
     BasicNorm,
     ConditionalNorm,
     EmotionBelief,
+    FaceBelief,
     GestureAction,
     Goal,
     InferredBelief,
@@ -682,11 +683,15 @@ class AgentSpeakGenerator:
         :return: An AstLiteral representing the semantic belief.
         """
         return AstLiteral(self.slugify(sb))
-    
+
     @_astify.register
     def _(self, eb: EmotionBelief) -> AstExpression:
         return AstLiteral("emotion_detected", [AstAtom(eb.emotion)])
 
+    @_astify.register
+    def _(self, fb: FaceBelief) -> AstExpression:
+        return AstLiteral("face_present")
+
     @_astify.register
     def _(self, ib: InferredBelief) -> AstExpression:
         """