fix(site-runtime): resolve SiteRuntime-001/002/003 — route data-sourced writes to DCL, real per-attribute API results, race-free redeploy

src/ScadaLink.SiteRuntime/Scripts/ScriptRuntimeContext.cs

@@ -99,18 +99,31 @@ public class ScriptRuntimeContext
     }
 
     /// <summary>
-    /// Sets an attribute value. For data-connected attributes, forwards to DCL via Instance Actor.
-    /// For static attributes, updates in-memory and persists to SQLite via Instance Actor.
-    /// All mutations serialized through the Instance Actor mailbox.
+    /// Sets an attribute value. For data-connected attributes the Instance Actor
+    /// forwards the write to the DCL, which writes the physical device; the
+    /// in-memory value is not optimistically updated. For static attributes the
+    /// Instance Actor updates the in-memory value and persists the override to
+    /// SQLite. All mutations are serialized through the Instance Actor mailbox.
+    ///
+    /// The write is awaited so that a device-write failure on a data-connected
+    /// attribute is surfaced synchronously to the calling script as an
+    /// <see cref="InvalidOperationException"/>.
     /// </summary>
-    public void SetAttribute(string attributeName, string value)
+    public async Task SetAttribute(string attributeName, string value)
     {
         var correlationId = Guid.NewGuid().ToString();
         var command = new SetStaticAttributeCommand(
             correlationId, _instanceName, attributeName, value, DateTimeOffset.UtcNow);
 
-        // Tell (fire-and-forget) — mutation serialized through Instance Actor
-        _instanceActor.Tell(command);
+        // Ask — mutation serialized through the Instance Actor mailbox; the reply
+        // carries the device-write outcome for data-connected attributes.
+        var response = await _instanceActor.Ask<SetStaticAttributeResponse>(command, _askTimeout);
+
+        if (!response.Success)
+        {
+            throw new InvalidOperationException(
+                $"SetAttribute('{attributeName}') failed: {response.ErrorMessage}");
+        }
     }
 
     /// <summary>