feat(csharp): expose snapshot imageUri in the C# SDK

Add ImageUri to the SnapshotInfo model and parse imageUri from the response in SandboxesAdapter.

Author: Ferran Pons Serra

sdks/sandbox/csharp/src/OpenSandbox/Adapters/SandboxesAdapter.cs

@@ -418,7 +418,10 @@ private static SnapshotInfo ParseSnapshotInfo(JsonElement element)
                     ? ParseIsoDate("lastTransitionAt", lastTransitionAt)
                     : null
             },
-            CreatedAt = ParseIsoDate("createdAt", element.GetProperty("createdAt"))
+            CreatedAt = ParseIsoDate("createdAt", element.GetProperty("createdAt")),
+            ImageUri = element.TryGetProperty("imageUri", out var imageUri) && imageUri.ValueKind != JsonValueKind.Null
+                ? imageUri.GetString()
+                : null
         };
     }
 

sdks/sandbox/csharp/src/OpenSandbox/Models/Sandboxes.cs

@@ -974,6 +974,13 @@ public class SnapshotInfo
 
     [JsonPropertyName("createdAt")]
     public required DateTime CreatedAt { get; set; }
+
+    /// <summary>
+    /// Portable OCI image reference for a Ready snapshot, usable to restore a sandbox (e.g. across
+    /// clusters). Populated once the snapshot is Ready; null otherwise.
+    /// </summary>
+    [JsonPropertyName("imageUri")]
+    public string? ImageUri { get; set; }
 }
 
 /// <summary>