# Telemetry Context Propagation Library

## Module
Telemetry

## Status
IMPLEMENTED

## Description
Shared telemetry context propagation library providing standardized trace/span ID injection, tenant context threading, and PII scrubbing across all platform services.

## Implementation Details
- **ITelemetryContextAccessor**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/ITelemetryContextAccessor.cs` -- `Context` / `Current` accessor for ambient telemetry context
- **TelemetryContextAccessor**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TelemetryContextAccessor.cs` -- AsyncLocal-based implementation
- **TelemetryContext**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TelemetryContext.cs` -- context model with trace/span ID, tenant, service identity
- **TelemetryContextPropagationMiddleware**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TelemetryContextPropagationMiddleware.cs` -- ASP.NET middleware for HTTP context propagation
- **TelemetryPropagationMiddleware**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TelemetryPropagationMiddleware.cs` -- additional propagation middleware
- **TelemetryPropagationHandler**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TelemetryPropagationHandler.cs` -- HTTP client handler for outbound context propagation
- **TelemetryContextPropagator**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TelemetryContextPropagator.cs` -- W3C trace context propagation
- **TelemetryContextJobScope**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TelemetryContextJobScope.cs` -- context scoping for background jobs
- **GrpcContextInterceptors**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/GrpcContextInterceptors.cs` -- gRPC interceptors for context propagation
- **CliTelemetryContext**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/CliTelemetryContext.cs` -- CLI-specific context for command telemetry
- **Tests**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core.Tests/TelemetryContextAccessorTests.cs`, `TelemetryContextTests.cs`, `TelemetryPropagationHandlerTests.cs`, `TelemetryPropagationMiddlewareTests.cs`, `CliTelemetryContextTests.cs`
- **Source**: SPRINT_0174_0001_0001_telemetry.md

## E2E Test Plan
- [ ] Verify trace/span IDs propagate across HTTP service boundaries via middleware
- [ ] Test tenant context threads through all service calls in a request
- [ ] Verify outbound HTTP calls include propagated context via TelemetryPropagationHandler
- [ ] Test gRPC interceptors propagate context for inter-service gRPC calls
- [ ] Verify background job scope correctly inherits and isolates telemetry context
- [ ] Test CLI telemetry context attaches command metadata to spans