feat: apply new agent naming standards

Expanding abbreviations to remove ambiguity, simplifying agent names to reduce repetition.

ref: N25B-257

src/control_backend/agents/perception/__init__.py

@@ -0,0 +1,4 @@
+from .transcription_agent.transcription_agent import (
+    TranscriptionAgent as TranscriptionAgent,
+)
+from .vad_agent import VADAgent as VADAgent