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/StellaOps.Concelier.WebService/Options/ConcelierOptions.cs

@@ -15,6 +15,8 @@ public sealed class ConcelierOptions
     public AuthorityOptions Authority { get; set; } = new();
 
     public MirrorOptions Mirror { get; set; } = new();
+
+    public FeaturesOptions Features { get; set; } = new();
 
     public sealed class StorageOptions
     {
@@ -135,4 +137,13 @@ public sealed class ConcelierOptions
 
         public int MaxDownloadRequestsPerHour { get; set; } = 1200;
     }
+
+    public sealed class FeaturesOptions
+    {
+        public bool NoMergeEnabled { get; set; }
+
+        public bool LnmShadowWrites { get; set; } = true;
+
+        public IList<string> MergeJobAllowlist { get; } = new List<string>();
+    }
 }

src/Concelier/StellaOps.Concelier.WebService/Options/ConcelierOptionsPostConfigure.cs

@@ -17,7 +17,8 @@ public static class ConcelierOptionsPostConfigure
     {
         ArgumentNullException.ThrowIfNull(options);
 
-        options.Authority ??= new ConcelierOptions.AuthorityOptions();
+        options.Authority ??= new ConcelierOptions.AuthorityOptions();
+        options.Features ??= new ConcelierOptions.FeaturesOptions();
 
         var authority = options.Authority;
         if (string.IsNullOrWhiteSpace(authority.ClientSecret)