feat: Add Go module and workspace test fixtures

- Created expected JSON files for Go modules and workspaces.
- Added go.mod and go.sum files for example projects.
- Implemented private module structure with expected JSON output.
- Introduced vendored dependencies with corresponding expected JSON.
- Developed PostgresGraphJobStore for managing graph jobs.
- Established SQL migration scripts for graph jobs schema.
- Implemented GraphJobRepository for CRUD operations on graph jobs.
- Created IGraphJobRepository interface for repository abstraction.
- Added unit tests for GraphJobRepository to ensure functionality.

src/__Libraries/StellaOps.Infrastructure.Postgres/Migrations/MigrationServiceExtensions.cs

@@ -219,7 +219,7 @@ public sealed record PendingMigrationInfo(string Name, MigrationCategory Categor
 /// <summary>
 /// Implementation of migration status service.
 /// </summary>
-internal sealed class MigrationStatusService : IMigrationStatusService
+public sealed class MigrationStatusService : IMigrationStatusService
 {
     private readonly string _connectionString;
     private readonly string _schemaName;