# Concelier LNM Linkset Cache with Telemetry

## Module
Concelier

## Status
IMPLEMENTED

## Description
PostgreSQL-backed deterministic cache for Link-Not-Merge advisory linksets with telemetry instrumentation, OpenAPI spec, and deprecation headers. While "Link-Not-Merge Advisory Architecture" is in the known list, this specific linkset caching with persistence and telemetry is a distinct implementation detail.

## Implementation Details
- **Modules**: `src/Concelier/__Libraries/StellaOps.Concelier.Core/Linksets/`, `src/Concelier/__Libraries/StellaOps.Concelier.Persistence/`, `src/Concelier/__Libraries/StellaOps.Concelier.Cache.Valkey/`
- **Key Classes**:
  - `LinksetCorrelationService` (`src/Concelier/__Libraries/StellaOps.Concelier.Core/Linksets/LinksetCorrelationService.cs`) - main service for linkset correlation and caching
  - `LinksetCorrelationV2` (`src/Concelier/__Libraries/StellaOps.Concelier.Core/Linksets/LinksetCorrelationV2.cs`) - V2 algorithm for linkset correlation
  - `LinksetCorrelation` (`src/Concelier/__Libraries/StellaOps.Concelier.Core/Linksets/LinksetCorrelation.cs`) - V1 linkset correlation logic
  - `ValkeyAdvisoryCacheService` (`src/Concelier/__Libraries/StellaOps.Concelier.Cache.Valkey/ValkeyAdvisoryCacheService.cs`) - Valkey-backed caching layer
  - `AdvisoryCacheKeys` (`src/Concelier/__Libraries/StellaOps.Concelier.Cache.Valkey/AdvisoryCacheKeys.cs`) - deterministic cache key generation
- **Interfaces**: `ILinksetCorrelationService`, `IAdvisoryCacheService`
- **Source**: Sprint 0112 (batch_14/file_13.md)

## E2E Test Plan
- [ ] Request a linkset for a known CVE and verify the correlation result is returned
- [ ] Verify caching: request the same linkset twice and confirm the second call is served from cache
- [ ] Verify telemetry: confirm cache hit/miss metrics are emitted via OpenTelemetry
- [ ] Verify determinism: identical linkset inputs produce identical cache keys via `AdvisoryCacheKeys`
- [ ] Verify V2 algorithm: use `LinksetCorrelationV2` and verify improved correlation accuracy over V1