[dotnet-code] Consolidate workflow edge registration

[michelle-clayton-work]

Centralize workflow builder edge insertion behind an unexported helper so direct, fan-out, and fan-in edge paths share the same internal registration shape.

[Copilot]

Pull request overview

This PR refactors the workflow Builder to centralize edge registration into a single unexported helper, so direct, fan-out, and fan-in edge creation paths all insert edges into the internal edges map consistently.

Changes:

• Replaced direct wb.edges[sourceID] = append(...) writes with a shared addEdgeForSource helper.
• Added the unexported addEdgeForSource(sourceID string, edge Edge) method to consolidate insertion logic across edge-building methods.

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[github-actions]

Cross-Repo API Consistency Review

Result: ✅ No parity issues — out of scope for cross-repo consistency review.

This PR extracts one repeated internal map-append pattern into an unexported helper method (addEdgeForSource). The three public Builder methods that call it — AddDirectEdge, AddFanOutEdge, and AddFanInBarrierEdge — are unchanged in signature, semantics, and observable behavior.

Because the change is a pure internal refactor with no effect on exported Go APIs, defaults, or runtime behavior, there is nothing to compare against the upstream .NET or Python implementations.

Generated by Go API Consistency Review Agent for issue #352 · 28.5 AIC · ⌖ 12.4 AIC · ⊞ 26.8K · ◷