feat: wire ExternalSystem, Database, and Notify APIs into script runtime

IServiceProvider now flows through the actor chain (DeploymentManagerActor
→ InstanceActor → ScriptActor → ScriptExecutionActor) so scripts can
resolve IExternalSystemClient, IDatabaseGateway, and
INotificationDeliveryService from DI. ScriptGlobals exposes ExternalSystem,
Database, Notify, and Scripts as top-level properties so scripts can use
them without the Instance. prefix.

src/ScadaLink.SiteRuntime/Actors/DeploymentManagerActor.cs

@@ -32,6 +32,7 @@ public class DeploymentManagerActor : ReceiveActor, IWithTimers
     private readonly ILogger<DeploymentManagerActor> _logger;
     private readonly IActorRef? _dclManager;
     private readonly ISiteHealthCollector? _healthCollector;
+    private readonly IServiceProvider? _serviceProvider;
     private readonly Dictionary<string, IActorRef> _instanceActors = new();
     private int _totalDeployedCount;
 
@@ -45,7 +46,8 @@ public class DeploymentManagerActor : ReceiveActor, IWithTimers
         SiteRuntimeOptions options,
         ILogger<DeploymentManagerActor> logger,
         IActorRef? dclManager = null,
-        ISiteHealthCollector? healthCollector = null)
+        ISiteHealthCollector? healthCollector = null,
+        IServiceProvider? serviceProvider = null)
     {
         _storage = storage;
         _compilationService = compilationService;
@@ -54,6 +56,7 @@ public class DeploymentManagerActor : ReceiveActor, IWithTimers
         _options = options;
         _dclManager = dclManager;
         _healthCollector = healthCollector;
+        _serviceProvider = serviceProvider;
         _logger = logger;
 
         // Lifecycle commands
@@ -561,7 +564,8 @@ public class DeploymentManagerActor : ReceiveActor, IWithTimers
             _options,
             loggerFactory.CreateLogger<InstanceActor>(),
             _dclManager,
-            _healthCollector));
+            _healthCollector,
+            _serviceProvider));
 
         var actorRef = Context.ActorOf(props, instanceName);
         _instanceActors[instanceName] = actorRef;

src/ScadaLink.SiteRuntime/Actors/InstanceActor.cs

@@ -39,6 +39,7 @@ public class InstanceActor : ReceiveActor
     private readonly SiteRuntimeOptions _options;
     private readonly ILogger _logger;
     private readonly ISiteHealthCollector? _healthCollector;
+    private readonly IServiceProvider? _serviceProvider;
     private readonly Dictionary<string, object?> _attributes = new();
     private readonly Dictionary<string, string> _attributeQualities = new();
     private readonly Dictionary<string, AlarmState> _alarmStates = new();
@@ -64,7 +65,8 @@ public class InstanceActor : ReceiveActor
         SiteRuntimeOptions options,
         ILogger logger,
         IActorRef? dclManager = null,
-        ISiteHealthCollector? healthCollector = null)
+        ISiteHealthCollector? healthCollector = null,
+        IServiceProvider? serviceProvider = null)
     {
         _instanceUniqueName = instanceUniqueName;
         _storage = storage;
@@ -75,6 +77,7 @@ public class InstanceActor : ReceiveActor
         _logger = logger;
         _dclManager = dclManager;
         _healthCollector = healthCollector;
+        _serviceProvider = serviceProvider;
 
         // Deserialize the flattened configuration
         _configuration = JsonSerializer.Deserialize<FlattenedConfiguration>(configJson);
@@ -479,7 +482,8 @@ public class InstanceActor : ReceiveActor
                 _sharedScriptLibrary,
                 _options,
                 _logger,
-                _healthCollector));
+                _healthCollector,
+                _serviceProvider));
 
             var actorRef = Context.ActorOf(props, $"script-{script.CanonicalName}");
             _scriptActors[script.CanonicalName] = actorRef;

src/ScadaLink.SiteRuntime/Actors/ScriptActor.cs

@@ -31,6 +31,7 @@ public class ScriptActor : ReceiveActor, IWithTimers
     private readonly SiteRuntimeOptions _options;
     private readonly ILogger _logger;
     private readonly ISiteHealthCollector? _healthCollector;
+    private readonly IServiceProvider? _serviceProvider;
 
     private Script<object?>? _compiledScript;
     private ScriptTriggerConfig? _triggerConfig;
@@ -49,7 +50,8 @@ public class ScriptActor : ReceiveActor, IWithTimers
         SharedScriptLibrary sharedScriptLibrary,
         SiteRuntimeOptions options,
         ILogger logger,
-        ISiteHealthCollector? healthCollector = null)
+        ISiteHealthCollector? healthCollector = null,
+        IServiceProvider? serviceProvider = null)
     {
         _scriptName = scriptName;
         _instanceName = instanceName;
@@ -59,6 +61,7 @@ public class ScriptActor : ReceiveActor, IWithTimers
         _options = options;
         _logger = logger;
         _healthCollector = healthCollector;
+        _serviceProvider = serviceProvider;
         _minTimeBetweenRuns = scriptConfig.MinTimeBetweenRuns;
 
         // Parse trigger configuration
@@ -212,7 +215,8 @@ public class ScriptActor : ReceiveActor, IWithTimers
             replyTo,
             correlationId,
             _logger,
-            _healthCollector));
+            _healthCollector,
+            _serviceProvider));
 
         Context.ActorOf(props, executionId);
     }

src/ScadaLink.SiteRuntime/Actors/ScriptExecutionActor.cs

@@ -1,6 +1,8 @@
 using Akka.Actor;
 using Microsoft.CodeAnalysis.Scripting;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
+using ScadaLink.Commons.Interfaces.Services;
 using ScadaLink.Commons.Messages.ScriptExecution;
 using ScadaLink.HealthMonitoring;
 using ScadaLink.SiteRuntime.Scripts;
@@ -30,7 +32,8 @@ public class ScriptExecutionActor : ReceiveActor
         IActorRef replyTo,
         string correlationId,
         ILogger logger,
-        ISiteHealthCollector? healthCollector = null)
+        ISiteHealthCollector? healthCollector = null,
+        IServiceProvider? serviceProvider = null)
     {
         // Immediately begin execution
         var self = Self;
@@ -39,7 +42,7 @@ public class ScriptExecutionActor : ReceiveActor
         ExecuteScript(
             scriptName, instanceName, compiledScript, parameters, callDepth,
             instanceActor, sharedScriptLibrary, options, replyTo, correlationId,
-            self, parent, logger, healthCollector);
+            self, parent, logger, healthCollector, serviceProvider);
     }
 
     private static void ExecuteScript(
@@ -56,16 +59,31 @@ public class ScriptExecutionActor : ReceiveActor
         IActorRef self,
         IActorRef parent,
         ILogger logger,
-        ISiteHealthCollector? healthCollector)
+        ISiteHealthCollector? healthCollector,
+        IServiceProvider? serviceProvider)
     {
         var timeout = TimeSpan.FromSeconds(options.ScriptExecutionTimeoutSeconds);
 
         // CTS must be created inside the async lambda so it outlives this method
         _ = Task.Run(async () =>
         {
+            IServiceScope? serviceScope = null;
             using var cts = new CancellationTokenSource(timeout);
             try
             {
+                // Resolve integration services from DI (scoped lifetime)
+                IExternalSystemClient? externalSystemClient = null;
+                IDatabaseGateway? databaseGateway = null;
+                INotificationDeliveryService? notificationService = null;
+
+                if (serviceProvider != null)
+                {
+                    serviceScope = serviceProvider.CreateScope();
+                    externalSystemClient = serviceScope.ServiceProvider.GetService<IExternalSystemClient>();
+                    databaseGateway = serviceScope.ServiceProvider.GetService<IDatabaseGateway>();
+                    notificationService = serviceScope.ServiceProvider.GetService<INotificationDeliveryService>();
+                }
+
                 var context = new ScriptRuntimeContext(
                     instanceActor,
                     self,
@@ -74,7 +92,10 @@ public class ScriptExecutionActor : ReceiveActor
                     options.MaxScriptCallDepth,
                     timeout,
                     instanceName,
-                    logger);
+                    logger,
+                    externalSystemClient,
+                    databaseGateway,
+                    notificationService);
 
                 var globals = new ScriptGlobals
                 {
@@ -123,6 +144,8 @@ public class ScriptExecutionActor : ReceiveActor
             }
             finally
             {
+                // Dispose the DI scope (and scoped services) after script execution completes
+                serviceScope?.Dispose();
                 // Stop self after execution completes
                 self.Tell(PoisonPill.Instance);
             }

src/ScadaLink.SiteRuntime/Scripts/ScriptCompilationService.cs

@@ -178,4 +178,28 @@ public class ScriptGlobals
     public IReadOnlyDictionary<string, object?> Parameters { get; set; } =
         new Dictionary<string, object?>();
     public CancellationToken CancellationToken { get; set; }
+
+    /// <summary>
+    /// Top-level ExternalSystem access for scripts (delegates to Instance.ExternalSystem).
+    /// Usage: ExternalSystem.Call("systemName", "methodName", params)
+    /// </summary>
+    public ScriptRuntimeContext.ExternalSystemHelper ExternalSystem => Instance.ExternalSystem;
+
+    /// <summary>
+    /// Top-level Database access for scripts (delegates to Instance.Database).
+    /// Usage: Database.Connection("name") or Database.CachedWrite("name", "sql", params)
+    /// </summary>
+    public ScriptRuntimeContext.DatabaseHelper Database => Instance.Database;
+
+    /// <summary>
+    /// Top-level Notify access for scripts (delegates to Instance.Notify).
+    /// Usage: Notify.To("listName").Send("subject", "message")
+    /// </summary>
+    public ScriptRuntimeContext.NotifyHelper Notify => Instance.Notify;
+
+    /// <summary>
+    /// Top-level Scripts access for shared script calls (delegates to Instance.Scripts).
+    /// Usage: Scripts.CallShared("scriptName", params)
+    /// </summary>
+    public ScriptRuntimeContext.ScriptCallHelper Scripts => Instance.Scripts;
 }