Bug: Embedded sub-workflows don't collapse when finished

[jakobklippel]

Summary

Embedded sub-workflows in Studio stay expanded after the child workflow completes. They should auto-collapse when the child reaches a terminal state (success / failure).

Steps to reproduce

1. Run a parent workflow that calls a sub-workflow via subWorkflow.run() and saves a LinkDocument with embed: true (e.g. show: 'inline').
2. Open the parent workflow in Studio — the embedded child renders inline, expanded.
3. Wait for the sub-workflow to finish.

Expected behaviour

The embedded sub-workflow card auto-collapses on completion. Reloading the page also shows it collapsed.

Actual behaviour

The card stays expanded indefinitely. Reloading still shows it expanded.

Affected area

• Package: @loopstack/loopstack-studio
• Files:
  • loopstack/frontend/studio/src/components/loopstack-elements/link.tsx (LinkCard, line ~32)
  • loopstack/frontend/studio/src/features/documents/renderers/LinkMessageRenderer.tsx
  • loopstack/packages/core — LinkDocument's expanded field written once at creation, never updated

Root cause (from investigation)

• LinkCard initializes expanded from defaultExpanded once and never reacts to prop changes:

  const [expanded, setExpanded] = useState(defaultExpanded ?? false);

• The live status prop is plumbed correctly: LinkMessageRenderer uses useChildWorkflows and maps state via mapWorkflowStateToStatus. But LinkCard only consumes status for icon color (statusColorMap[status], line ~83). No effect reacts to status becoming success / failure.
• The persisted expanded field on LinkDocument is set to true at queue time and never updated when the child completes — so on reload the embed also comes back expanded.

Environment

• Branch / commit: TBD
• Node / npm / OS: TBD

Additional context

Related convention: sub-workflow embedding stores a LinkDocument with embed: true after subWorkflow.run() so Studio renders it inline.

[jakobklippel]

Linked to PR #215: #215