fix(workflows): handle path segments whose port is a container's collection port

[sfmskywalker]

Closes #1018.

The defect, reproduced

Selecting an activity by id through the path the instance viewer uses (SelectActivityByActivityIdAsync → GetPathSegmentsAsync) crashed the designer when the activity sat inside a container that is not a flowchart, such as a BpmnProcess. The server's path-segments endpoint names such a segment's port after the container's reflected child-list property, PortName = "Activities". That comes from PropertyBasedActivityResolver over Container.Activities. No port provider yields that port, so:

• GetEmbeddedActivity resolved it through the embedded-port path and called AsObject() on the activities JSON array, throwing InvalidOperationException;
• GetBreadcrumbItems did ports.First(...) on a port that does not exist.

What changed

Both changes are in DiagramDesignerWrapper.razor.cs:

• A segment whose port names a collection property on the container (its own list of child activities) now resolves to the container itself, instead of going through an embedded-port lookup. The children stay reachable through that list. Descriptor-declared embedded ports (If.Then, a flowchart in a sequence) resolve as before.
• Breadcrumb building no longer throws. When no descriptor port matches the segment's port, the crumb falls back to the activity's display name, as the issue asked.

Verification

cd src/modules/Elsa.Studio.Workflows.Designer/ClientLib && npm run build
dotnet build Elsa.Studio.sln --configuration Release
dotnet test src/modules/Elsa.Studio.Workflows.Tests --configuration Release --no-build --framework net10.0   # 337/337

BreadcrumbCollectionPortSegmentTests stubs the path segments in the exact shape elsa-core's endpoint returns and selects through the instance-viewer path. It fails before the fix with InvalidOperationException and passes after, confirmed independently by the spec reviewer.

Review: one iteration on the standards and spec axes. Recorded as won't-fix: the breadcrumb fallback is deliberately generic, as the issue asked; and a private helper's doc comment has no <summary> tag, which the XML-doc rule only requires on public members.

🤖 Generated with Claude Code

[greptile-apps]

Confidence Score: 5/5

Safe to merge.

Summary

• This update fixes navigation into nested workflow activity collections. Collection-valued path segments now resolve to their owning container, breadcrumbs fall back to the container name when no descriptor port matches, and the regression test verifies selection of the nested child’s bound BPMN element.

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