Add workflow context propagation sample

[atrauzzi]

Supercedes #1310

Summary

• Adds a new .NET quickstart demonstrating workflow history propagation (Dapr 1.18 feature)
• Ported from @cicoyle's canonical Go quickstart: dapr/quickstarts#1315 — same patient intake / e-prescribing scenario, same 3-level hierarchy, same workflow names
• Mirrors the Python sibling: dapr/quickstarts#1309
• Builds on .NET SDK support landed in dapr/dotnet-sdk#1802 and runtime support in dapr/dapr#9810
• Companion docs PR: dapr/docs#5174

Scenario

Patient intake / e-prescribing pipeline. A compliance audit and a pharmacy dispense step refuse to act unless the propagated history proves the required upstream checks (insurance, allergies, drug interactions) actually ran.

PatientIntake (root)
  └─ VerifyInsurance         (activity, no propagation)
  └─ PrescribeMedication     (child wf, HistoryPropagationScope.Lineage)
        └─ CheckAllergies                 (activity, no propagation)
        └─ ScreenDrugInteractions         (activity, no propagation)
        └─ ComplianceAudit                (grandchild wf, HistoryPropagationScope.Lineage)
        |      reads PatientIntake + PrescribeMedication events
        └─ DispenseMedicationWorkflow     (grandchild wf, HistoryPropagationScope.OwnHistory)
               reads PrescribeMedication events only
               └─ DispenseMedication       (activity)

.NET API used (from 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 the Python/Go siblings

The Python SDK and Go SDK both support a propagation argument on bare activity calls, so they call DispenseMedication as a plain activity with 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, DispenseMedicationActivity is wrapped in DispenseMedicationWorkflow (a child workflow). This is the correct .NET idiom for the v1.18 API; it is not a gap in the sample.

Replay safety

All Console.WriteLine calls inside workflows are guarded by if (!ctx.IsReplaying) so they only fire on the live execution, not on each durable replay.

Status — DRAFT

• 7 files added, dotnet build not validated locally (dotnet SDK not on path — 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 dapr/go-sdk#823 merges, (2) Python sibling #1309 lands, (3) docs PR #5174 lands

Test plan

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

References

• Go quickstart this is ported from: dapr/quickstarts#1315 (@cicoyle)
• Proposal: dapr/proposals#102
• Runtime: dapr/dapr#9810
• .NET SDK: dapr/dotnet-sdk#1802
• Go SDK reference: dapr/go-sdk#823
• Python sibling: dapr/quickstarts#1309
• Docs: dapr/docs#5174
• 1.18 endgame: dapr/dapr#9856

[alicejgibbons]

mostly long comments but a couple things

[alicejgibbons]

few more changes