✨(backend) add metadata collection of VAD, connection and chat events

Introduce MetadataCollector and MetadataCollectorService classes to
centralize the collection and storage of user connections, VAD events,
and chat messages. This creates a structured foundation for future speaker
assignment logic based on voice activity detection. Add tests for this new
feature.

src/agents/pyproject.toml

@@ -9,7 +9,8 @@ dependencies = [
     "livekit-plugins-silero==1.4.5",
     "livekit-plugins-kyutai-lasuite==0.0.6",
     "python-dotenv==1.2.2",
-    "protobuf==6.33.5"
+    "protobuf==6.33.5",
+    "minio==7.2.15"
 ]
 
 [project.optional-dependencies]
@@ -17,6 +18,9 @@ dev = [
     "ruff==0.15.6",
 ]
 
+[tool.setuptools]
+py-modules = ["multi_user_transcriber", "metadata_collector", "exceptions"]
+
 [build-system]
 requires = ["setuptools>=61.0"]
 build-backend = "setuptools.build_meta"