feat(template-engine): resolve TemplateEngine-002 — per-slot alarm override for derived templates

Adds IsInherited/LockedInDerived to the TemplateAlarm entity (mirroring the
attribute/script override model), an EF migration, base-alarm copy-on-derive,
inherited-alarm flattening skip, and LockedInDerived override-rejection validation.

tests/ScadaLink.TemplateEngine.Tests/TemplateServiceTests.cs

@@ -566,6 +566,123 @@ public class TemplateServiceTests
         Assert.Contains("locked by base template 'Sensor'", result.Error);
     }
 
+    [Fact]
+    public async Task AddComposition_CopiesAlarmsAsInherited()
+    {
+        var moduleTemplate = new Template("Module") { Id = 2 };
+        moduleTemplate.Alarms.Add(new TemplateAlarm("HighTemp")
+        {
+            Id = 30,
+            TemplateId = 2,
+            TriggerType = AlarmTriggerType.RangeViolation,
+            TriggerConfiguration = "{\"attributeName\":\"Temp\",\"high\":100}",
+            PriorityLevel = 5,
+            Description = "Too hot"
+        });
+        var template = new Template("Parent") { Id = 1 };
+
+        _repoMock.Setup(r => r.GetTemplateByIdAsync(1, It.IsAny<CancellationToken>())).ReturnsAsync(template);
+        _repoMock.Setup(r => r.GetTemplateByIdAsync(2, It.IsAny<CancellationToken>())).ReturnsAsync(moduleTemplate);
+        _repoMock.Setup(r => r.GetAllTemplatesAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Template> { template, moduleTemplate });
+
+        Template? captured = null;
+        _repoMock.Setup(r => r.AddTemplateAsync(It.IsAny<Template>(), It.IsAny<CancellationToken>()))
+            .Callback<Template, CancellationToken>((t, _) => captured = t)
+            .Returns(Task.CompletedTask);
+
+        var result = await _service.AddCompositionAsync(1, 2, "myModule", "admin");
+
+        Assert.True(result.IsSuccess);
+        Assert.NotNull(captured);
+        Assert.Single(captured!.Alarms);
+        var copied = captured.Alarms.First();
+        Assert.Equal("HighTemp", copied.Name);
+        Assert.True(copied.IsInherited);
+        Assert.False(copied.LockedInDerived);
+        Assert.Equal(AlarmTriggerType.RangeViolation, copied.TriggerType);
+        Assert.Equal(5, copied.PriorityLevel);
+        Assert.Equal("Too hot", copied.Description);
+    }
+
+    [Fact]
+    public async Task UpdateAlarm_LockedInDerivedBase_RejectsOnDerived()
+    {
+        var existing = new TemplateAlarm("HighTemp")
+        {
+            Id = 300,
+            TemplateId = 77,
+            TriggerType = AlarmTriggerType.RangeViolation,
+            PriorityLevel = 5,
+            IsInherited = true
+        };
+        var baseTemplate = new Template("Sensor") { Id = 2 };
+        baseTemplate.Alarms.Add(new TemplateAlarm("HighTemp")
+        {
+            Id = 30,
+            TemplateId = 2,
+            TriggerType = AlarmTriggerType.RangeViolation,
+            LockedInDerived = true
+        });
+        var derived = new Template("Parent.slot") { Id = 77, ParentTemplateId = 2, IsDerived = true };
+
+        _repoMock.Setup(r => r.GetTemplateAlarmByIdAsync(300, It.IsAny<CancellationToken>())).ReturnsAsync(existing);
+        _repoMock.Setup(r => r.GetTemplateByIdAsync(77, It.IsAny<CancellationToken>())).ReturnsAsync(derived);
+        _repoMock.Setup(r => r.GetTemplateByIdAsync(2, It.IsAny<CancellationToken>())).ReturnsAsync(baseTemplate);
+        _repoMock.Setup(r => r.GetAllTemplatesAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Template> { baseTemplate, derived });
+
+        var proposed = new TemplateAlarm("HighTemp")
+        {
+            TriggerType = AlarmTriggerType.RangeViolation,
+            PriorityLevel = 99,
+            IsInherited = false
+        };
+        var result = await _service.UpdateAlarmAsync(300, proposed, "admin");
+
+        Assert.True(result.IsFailure);
+        Assert.Contains("locked by base template 'Sensor'", result.Error);
+    }
+
+    [Fact]
+    public async Task UpdateAlarm_DerivedOverride_PersistsIsInheritedFalse()
+    {
+        var existing = new TemplateAlarm("HighTemp")
+        {
+            Id = 300,
+            TemplateId = 77,
+            TriggerType = AlarmTriggerType.RangeViolation,
+            PriorityLevel = 5,
+            IsInherited = true
+        };
+        var baseTemplate = new Template("Sensor") { Id = 2 };
+        baseTemplate.Alarms.Add(new TemplateAlarm("HighTemp")
+        {
+            Id = 30,
+            TemplateId = 2,
+            TriggerType = AlarmTriggerType.RangeViolation
+        });
+        var derived = new Template("Parent.slot") { Id = 77, ParentTemplateId = 2, IsDerived = true };
+
+        _repoMock.Setup(r => r.GetTemplateAlarmByIdAsync(300, It.IsAny<CancellationToken>())).ReturnsAsync(existing);
+        _repoMock.Setup(r => r.GetTemplateByIdAsync(77, It.IsAny<CancellationToken>())).ReturnsAsync(derived);
+        _repoMock.Setup(r => r.GetTemplateByIdAsync(2, It.IsAny<CancellationToken>())).ReturnsAsync(baseTemplate);
+        _repoMock.Setup(r => r.GetAllTemplatesAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Template> { baseTemplate, derived });
+
+        var proposed = new TemplateAlarm("HighTemp")
+        {
+            TriggerType = AlarmTriggerType.RangeViolation,
+            PriorityLevel = 99,
+            IsInherited = false
+        };
+        var result = await _service.UpdateAlarmAsync(300, proposed, "admin");
+
+        Assert.True(result.IsSuccess);
+        Assert.False(result.Value.IsInherited);
+        Assert.Equal(99, result.Value.PriorityLevel);
+    }
+
     [Fact]
     public async Task UpdateAttribute_DerivedOverride_PersistsIsInheritedFalse()
     {