feat(runtime): per-script execution timeout overriding the global default (#9)

Spec promised a per-script timeout but only the global ScriptExecutionTimeoutSeconds
existed. Add nullable TemplateScript.ExecutionTimeoutSeconds threaded through EF +
flattening (ResolvedScript) to ScriptExecutionActor/AlarmExecutionActor, which use
perScript ?? global for the execution CTS. Includes the EF migration for the new column.

src/ZB.MOM.WW.ScadaBridge.Transport/Import/BundleImporter.cs

@@ -2339,6 +2339,7 @@ public sealed class BundleImporter : IBundleImporter
                 ParameterDefinitions = s.ParameterDefinitions,
                 ReturnDefinition = s.ReturnDefinition,
                 MinTimeBetweenRuns = s.MinTimeBetweenRuns,
+                ExecutionTimeoutSeconds = s.ExecutionTimeoutSeconds,
                 Source = "Template",
             });
         }

src/ZB.MOM.WW.ScadaBridge.Transport/Serialization/EntityDtos.cs

@@ -99,7 +99,10 @@ public sealed record TemplateScriptDto(
     string? ParameterDefinitions,
     string? ReturnDefinition,
     bool IsLocked,
-    TimeSpan? MinTimeBetweenRuns);
+    TimeSpan? MinTimeBetweenRuns,
+    // M2.5 (#9): per-script execution timeout (seconds). Additive trailing field;
+    // null on bundles written before this field existed.
+    int? ExecutionTimeoutSeconds = null);
 
 public sealed record TemplateCompositionDto(
     string InstanceName,

src/ZB.MOM.WW.ScadaBridge.Transport/Serialization/EntitySerializer.cs

@@ -74,7 +74,8 @@ public sealed class EntitySerializer
                         ParameterDefinitions: s.ParameterDefinitions,
                         ReturnDefinition: s.ReturnDefinition,
                         IsLocked: s.IsLocked,
-                        MinTimeBetweenRuns: s.MinTimeBetweenRuns)).ToList(),
+                        MinTimeBetweenRuns: s.MinTimeBetweenRuns,
+                        ExecutionTimeoutSeconds: s.ExecutionTimeoutSeconds)).ToList(),
                     Compositions: t.Compositions.Select(c => new TemplateCompositionDto(
                         InstanceName: c.InstanceName,
                         ComposedTemplateName: templateNameById.TryGetValue(c.ComposedTemplateId, out var cn) ? cn : string.Empty)).ToList());
@@ -227,6 +228,7 @@ public sealed class EntitySerializer
                         ReturnDefinition = s.ReturnDefinition,
                         IsLocked = s.IsLocked,
                         MinTimeBetweenRuns = s.MinTimeBetweenRuns,
+                        ExecutionTimeoutSeconds = s.ExecutionTimeoutSeconds,
                     });
                 }
                 return t;