feat(agent-call): add contract-driven mock executor

deploy/mock.env.example

@@ -0,0 +1,9 @@
+# Synthetic local values only. Never use this file for production credentials.
+RABBITMQ_DEFAULT_USER=agent_call_mock
+RABBITMQ_DEFAULT_PASS=replace-before-start
+RABBITMQ_URL=amqp://agent_call_mock:replace-before-start@rabbitmq:5672/%2f
+# JSON map: token -> tenant IDs and scopes. Inject through a secret manager in real deployments.
+HTTP_TOKENS={"local":{"tenant_ids":["tenant-demo"],"scopes":["outbound.read","outbound.control","recording.upload","recording.complete"]}}
+AGENT_CALL_MODE=mock
+BROKER_MODE=rabbit
+AGENT_CALL_PORT=18080