Bootstrap one metered owner cycle against a pinned standalone runtime

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a07ff8-19d0-7820-b4d0-1353833cb7fc

rein_aharness/messages_owner.py

@@ -40,6 +40,8 @@ class MessagesOwner:
     provider_key: str = field(repr=False)
     upstream_url: str = "https://api.anthropic.com"
     allow_test_http: bool = False
+    runtime_path: Path | None = None
+    runtime_sha256: str | None = None
 
     @contextmanager
     def activate(self, run, config, spend, profile, cancel: ExecutionCancel):
@@ -100,6 +102,7 @@ class MessagesOwner:
                     socket_path, token, profile.sandbox_profile, "agt",
                     config.execution_project, run.id,
                     private_paths=(spend.path.parent,),
+                    runtime_path=self.runtime_path, runtime_sha256=self.runtime_sha256,
                 )
                 server.start()
                 timer.start()