* feat(custom-blocks): log and bill child runs in the publisher's workspace
* fix(custom-blocks): sanitize every boundary failure and classify it for consumers
* fix(custom-blocks): surface a cancelled child as cancelled, not a generic failure
* fix(custom-blocks): share one large-value id list so nested blocks propagate
* fix(custom-blocks): add a durable cancel backstop to the child bridge
* fix(tools): carry Sim's own status through the tool-response boundary
* fix(custom-blocks): stop forwarding the publisher's personal quota to consumers
* fix(custom-blocks): correlate agent-tool runs to the real invoking execution
* fix(custom-blocks): plumb the invoking execution id and abort signal to agent tools
* fix(agent): forward the execution id through the provider payload
* fix(executor): stop adopting an upstream target's HTTP status as our own
* fix(custom-blocks): drain child log finalization when the parent is cancelled
* fix(custom-blocks): require curated outputs instead of exposing the whole result
* fix(custom-blocks): track the whole child run, not just its finalization