feat: add agent runtime foundation

Author: openai0229

Cargo.lock

@@ -10,13 +10,15 @@ repository.workspace = true
 
 [dependencies]
 base64.workspace = true
+chat2db-agent = { path = "../chat2db-agent" }
 chat2db-contract = { path = "../chat2db-contract" }
 chat2db-engine-protocol = { path = "../chat2db-engine-protocol" }
 chat2db-java-bridge = { path = "../chat2db-java-bridge" }
 chat2db-storage = { path = "../chat2db-storage" }
 serde_json.workspace = true
 thiserror.workspace = true
 tokio.workspace = true
+tokio-util.workspace = true
 tracing.workspace = true
 uuid.workspace = true