OPC # 0001: Extract OPC into standalone repo

ControlPlane.Core/Interfaces/SagaContext.cs

@@ -0,0 +1,30 @@
+using ControlPlane.Core.Models;
+
+namespace ControlPlane.Core.Interfaces;
+
+/// <summary>
+/// Mutable context bag passed through every saga step.
+/// Steps read inputs and write outputs here so downstream steps can consume them.
+/// </summary>
+public class SagaContext
+{
+    public ProvisioningJob Job { get; init; } = default!;
+
+    // Written by DatabaseStep — connection string for the tenant's Postgres (shared or own)
+    public string? TenantConnectionString { get; set; }
+    public string? TenantStackName { get; set; }
+
+    // Written by KeycloakStep
+    public string? DayZeroUserSubjectId { get; set; }
+    public string? MagicLink { get; set; }
+
+    // Written by LaunchStep or PulumiStep — base URL for the provisioned tenant
+    public string? TenantApiBaseUrl { get; set; }
+
+    // Written by LaunchStep — primary app container name
+    public string? ContainerName { get; set; }
+
+    // Written by PulumiStep (DedicatedVM/Enterprise tier) — target host details for subsequent steps
+    public string? VmIpAddress { get; set; }
+    public string? VmSshKeyPath { get; set; }
+}