Extract TryResolveSubWorkflowDefinition that returns null instead of
throwing when a referenced workflow is missing from the library.
Use the tolerant variant in all graph-walking helpers that build
agent indexes, collect agent nodes, and find sub-workflow nodes.
These operations are used for activity UI enrichment and agent
identity resolution — they should degrade gracefully rather than
crash the turn.
The throwing ResolveSubWorkflowDefinition is now only used by
WorkflowRunner.CreateNodeRoute, which is the actual execution
path and correctly fails with a clear error if a reference is
truly missing.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Deep agent resolution in the sidecar now walks sub-workflow nodes so
nested agents carry subworkflowNodeId and subworkflowName on activity
events. New subworkflow-started / subworkflow-completed activity types
let the frontend track sub-workflow lifecycle.
The Activity panel groups nested agents under collapsible sub-workflow
cards with status badges, accent-colored left borders, and smooth
expand/collapse transitions. Cards auto-expand when a sub-workflow
starts running. Workflows without sub-workflow nodes render identically
to before.
Extracted AgentRow, SubWorkflowGroup, and shared accent constants to
a new components/activity/ feature directory. Added
resolveWorkflowAgentHierarchy and buildGroupedActivityRows for
hierarchical activity grouping with dynamic fallback for unresolved
sub-workflow agents.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
