feat: Implement approvals workflow and notifications integration

- Added approvals orchestration with persistence and workflow scaffolding.
- Integrated notifications insights and staged resume hooks.
- Introduced approval coordinator and policy notification bridge with unit tests.
- Added approval decision API with resume requeue and persisted plan snapshots.
- Documented the Excitor consensus API beta and provided JSON sample payload.
- Created analyzers to flag usage of deprecated merge service APIs.
- Implemented logging for artifact uploads and approval decision service.
- Added tests for PackRunApprovalDecisionService and related components.

src/Concelier/__Libraries/StellaOps.Concelier.Merge/Services/AdvisoryMergeService.cs

@@ -14,9 +14,10 @@ using StellaOps.Concelier.Storage.Mongo.Aliases;
 using StellaOps.Concelier.Storage.Mongo.MergeEvents;
 using System.Text.Json;
 
-namespace StellaOps.Concelier.Merge.Services;
-
-public sealed class AdvisoryMergeService
+namespace StellaOps.Concelier.Merge.Services;
+
+[Obsolete("AdvisoryMergeService is deprecated. Transition callers to Link-Not-Merge observation/linkset APIs (MERGE-LNM-21-002) and enable concelier:features:noMergeEnabled when ready.", DiagnosticId = "CONCELIER0001", UrlFormat = "https://stella-ops.org/docs/migration/no-merge")]
+public sealed class AdvisoryMergeService
 {
     private static readonly Meter MergeMeter = new("StellaOps.Concelier.Merge");
     private static readonly Counter<long> AliasCollisionCounter = MergeMeter.CreateCounter<long>(