[DRAFT] feat(dotnet): workflow context propagation quickstart

[nelson-parente]

Summary

• Adds a new .NET quickstart demonstrating workflow history propagation (Dapr 1.18 feature)
• Mirrors the Python sibling: [DRAFT] feat(python): workflow context propagation quickstart #1309 (same credit-card fraud-detection scenario, same 3-level hierarchy)
• Ported from the canonical Go reference: Feature workflow history propagation go-sdk#823 (cicoyle's feature/wf-ctx-propagation branch)
• Uses .NET SDK support landed in Feature: Workflow history propagation dotnet-sdk#1802 (merged 2026-05-12, "Feature: Workflow history propagation")
• Builds on runtime support in wf history ctx propagation dapr#9810
• Companion docs PR: Adding .NET SDK documentation for history propagation docs#5174 (.NET history propagation docs)

Scenario

Credit-card payment with fraud detection across a 3-level workflow hierarchy:

MerchantCheckout (root)
  └─ ValidateMerchant         (activity, no propagation)
  └─ ProcessPayment           (child wf, HistoryPropagationScope.Lineage)
        └─ ValidateCard               (activity, no propagation)
        └─ CheckSpendingLimits        (activity, no propagation)
        └─ FraudDetection             (grandchild wf, HistoryPropagationScope.Lineage)
        |      reads MerchantCheckout + ProcessPayment events
        └─ SettlementWorkflow         (grandchild wf, HistoryPropagationScope.OwnHistory)
               reads ProcessPayment events only
               └─ SettlePayment       (activity)

.NET API confirmed (dapr/dotnet-sdk#1802)

• HistoryPropagationScope enum: None, OwnHistory, Lineage
• ChildWorkflowTaskOptions(PropagationScope: HistoryPropagationScope.Lineage) — passed to CallChildWorkflowAsync
• WorkflowContext.GetPropagatedHistory() → PropagatedHistory?
• PropagatedHistory.FilterByWorkflowName(name) → filtered PropagatedHistory
• PropagatedHistoryEntry — has WorkflowName, AppId, InstanceId, Events
• PropagatedHistoryEvent — has EventId, Kind (HistoryEventKind), Timestamp

Key difference from Python sibling

The Python SDK supports propagation= on bare activity calls (call_activity()), so settle_payment is a plain activity receiving PropagationScope.OWN_HISTORY.

The .NET SDK v1.18 scopes HistoryPropagationScope to ChildWorkflowTaskOptions only — activity calls do not carry a propagation scope. To demonstrate identical OwnHistory trust-boundary semantics, SettlePayment is wrapped in a SettlementWorkflow child workflow. This is the correct .NET idiom; it is not a gap in the sample.

Status — DRAFT

• 7 files added, dotnet build not validated locally (dotnet SDK not in path on this machine — CI will catch compile errors)
• Smoke-test pending Dapr 1.18 RC sidecar + Dapr.Workflow 1.18.0-rc01 on NuGet
• Will be marked ready once: (1) Go reference Feature workflow history propagation go-sdk#823 merges, (2) Python sibling [DRAFT] feat(python): workflow context propagation quickstart #1309 lands, (3) docs PR #5174 lands

Test plan

• dotnet build clean
• dapr run -f . against Dapr 1.18 RC sidecar with Redis
• FraudDetection receives 2 propagated segments (MerchantCheckout + ProcessPayment) under Lineage
• SettlementWorkflow receives 1 propagated segment (ProcessPayment only) under OwnHistory
• MerchantCheckout segment correctly absent from SettlementWorkflow's history
• Older sidecar (pre-1.18): GetPropagatedHistory() returns null, sample exits gracefully
• CI passes on the .NET quickstart matrix

References

• Proposal: Workflow History propogation & signing proposals#102
• Runtime: wf history ctx propagation dapr#9810
• .NET SDK: Feature: Workflow history propagation dotnet-sdk#1802
• Go SDK reference: Feature workflow history propagation go-sdk#823
• Python sibling: [DRAFT] feat(python): workflow context propagation quickstart #1309
• Docs: Adding .NET SDK documentation for history propagation docs#5174
• 1.18 endgame: v1.18 Endgame dapr#9856