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/Scanner/StellaOps.Scanner.Worker/AssemblyInfo.cs

@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("StellaOps.Scanner.Worker.Tests")]