Phase 2 WP-1–13+23: Template Engine CRUD, composition, overrides, locking, collision detection, acyclicity

- WP-23: ITemplateEngineRepository full EF Core implementation
- WP-1: Template CRUD with deletion constraints (instances, children, compositions)
- WP-2–4: Attribute, alarm, script definitions with lock flags and override granularity
- WP-5: Shared script CRUD with syntax validation
- WP-6–7: Composition with recursive nesting and canonical naming
- WP-8–11: Override granularity, locking rules, inheritance/composition scope
- WP-12: Naming collision detection on canonical names (recursive)
- WP-13: Graph acyclicity (inheritance + composition cycles)
Core services: TemplateService, SharedScriptService, TemplateResolver,
LockEnforcer, CollisionDetector, CycleDetector. 358 tests pass.

tests/ScadaLink.TemplateEngine.Tests/Flattening/DeploymentPackageTests.cs

@@ -0,0 +1,118 @@
+using System.Text.Json;
+using ScadaLink.Commons.Types.Flattening;
+
+namespace ScadaLink.TemplateEngine.Tests.Flattening;
+
+public class DeploymentPackageTests
+{
+    [Fact]
+    public void DeploymentPackage_JsonSerializable()
+    {
+        var package = new DeploymentPackage
+        {
+            InstanceUniqueName = "PumpStation1",
+            DeploymentId = "dep-abc123",
+            RevisionHash = "sha256:abcdef1234567890",
+            DeployedBy = "admin@company.com",
+            DeployedAtUtc = new DateTimeOffset(2026, 3, 16, 12, 0, 0, TimeSpan.Zero),
+            Configuration = new FlattenedConfiguration
+            {
+                InstanceUniqueName = "PumpStation1",
+                TemplateId = 1,
+                SiteId = 1,
+                Attributes =
+                [
+                    new ResolvedAttribute
+                    {
+                        CanonicalName = "Temperature",
+                        Value = "25.0",
+                        DataType = "Double",
+                        BoundDataConnectionId = 100,
+                        BoundDataConnectionName = "OPC-Server1",
+                        BoundDataConnectionProtocol = "OpcUa",
+                        DataSourceReference = "ns=2;s=Temp"
+                    }
+                ],
+                Alarms =
+                [
+                    new ResolvedAlarm
+                    {
+                        CanonicalName = "HighTemp",
+                        TriggerType = "RangeViolation",
+                        PriorityLevel = 1
+                    }
+                ],
+                Scripts =
+                [
+                    new ResolvedScript
+                    {
+                        CanonicalName = "Monitor",
+                        Code = "var x = Attributes[\"Temperature\"].Value;"
+                    }
+                ]
+            },
+            PreviousRevisionHash = null
+        };
+
+        var json = JsonSerializer.Serialize(package);
+        Assert.NotNull(json);
+        Assert.Contains("PumpStation1", json);
+        Assert.Contains("sha256:abcdef1234567890", json);
+
+        var deserialized = JsonSerializer.Deserialize<DeploymentPackage>(json);
+        Assert.NotNull(deserialized);
+        Assert.Equal("PumpStation1", deserialized.InstanceUniqueName);
+        Assert.Equal("dep-abc123", deserialized.DeploymentId);
+        Assert.Single(deserialized.Configuration.Attributes);
+        Assert.Equal("Temperature", deserialized.Configuration.Attributes[0].CanonicalName);
+    }
+
+    [Fact]
+    public void DeploymentPackage_WithDiff_Serializable()
+    {
+        var package = new DeploymentPackage
+        {
+            InstanceUniqueName = "Inst1",
+            DeploymentId = "dep-1",
+            RevisionHash = "sha256:new",
+            DeployedBy = "admin",
+            DeployedAtUtc = DateTimeOffset.UtcNow,
+            Configuration = new FlattenedConfiguration { InstanceUniqueName = "Inst1" },
+            Diff = new ConfigurationDiff
+            {
+                InstanceUniqueName = "Inst1",
+                OldRevisionHash = "sha256:old",
+                NewRevisionHash = "sha256:new",
+                AttributeChanges =
+                [
+                    new DiffEntry<ResolvedAttribute>
+                    {
+                        CanonicalName = "Temp",
+                        ChangeType = DiffChangeType.Changed,
+                        OldValue = new ResolvedAttribute { CanonicalName = "Temp", Value = "25", DataType = "Double" },
+                        NewValue = new ResolvedAttribute { CanonicalName = "Temp", Value = "50", DataType = "Double" }
+                    }
+                ]
+            },
+            PreviousRevisionHash = "sha256:old"
+        };
+
+        var json = JsonSerializer.Serialize(package);
+        var deserialized = JsonSerializer.Deserialize<DeploymentPackage>(json);
+
+        Assert.NotNull(deserialized?.Diff);
+        Assert.True(deserialized.Diff.HasChanges);
+        Assert.Equal("sha256:old", deserialized.PreviousRevisionHash);
+    }
+
+    [Fact]
+    public void FlattenedConfiguration_DefaultValues()
+    {
+        var config = new FlattenedConfiguration();
+
+        Assert.Equal(string.Empty, config.InstanceUniqueName);
+        Assert.Empty(config.Attributes);
+        Assert.Empty(config.Alarms);
+        Assert.Empty(config.Scripts);
+    }
+}