fix: recover fixture activation raised during document open

Plant3D2026/P_Rec_Annot/src/PRecAnnot.Plant3D2026/FirstLimitedApplyAutomation.cs

@@ -195,6 +195,16 @@ internal sealed class FirstLimitedApplyAutomationCoordinator
             document.CommandCancelled += OnCommandCancelled;
             documentHandlersSubscribed = true;
             Transition(CoordinatorState.Running, "AutomationRunning");
+            // DocumentActivated can be raised synchronously by Open before the
+            // coordinator receives the returned Document. Confirm the current
+            // active document after assignment so that one missed event cannot
+            // strand the workflow waiting for another startup Idle.
+            if (ReferenceEquals(AcadApplication.DocumentManager.MdiActiveDocument, document))
+            {
+                fixtureDocumentActivated = true;
+                transitions.Add("FixtureDocumentActiveAfterOpen");
+                TryActivateProjectAndVerifyContext();
+            }
         }
         catch (System.Exception ex) { FailFromCallback("Start", ex, "AUTOMATION_START_FAILED"); }
     }

Plant3D2026/P_Rec_Annot/tests/PRecAnnot.Core.Tests/FoundationTests.cs

@@ -98,6 +98,15 @@ public sealed class FoundationTests
         Assert.Contains("FixtureDocumentActivated", source);
     }
 
+    [Fact] public void AutomationDocumentActivation_RecoversSynchronousOpenEvent()
+    {
+        var source = File.ReadAllText(Path.Combine(ProjectRoot, "src", "PRecAnnot.Plant3D2026", "FirstLimitedApplyAutomation.cs"));
+        var start = source[source.IndexOf("public void Start()", StringComparison.Ordinal)..source.IndexOf("private void CompleteLifecycleProbe", StringComparison.Ordinal)];
+        Assert.Contains("FixtureDocumentActiveAfterOpen", start);
+        Assert.Contains("ReferenceEquals(AcadApplication.DocumentManager.MdiActiveDocument, document)", start);
+        Assert.Contains("TryActivateProjectAndVerifyContext();", start);
+    }
+
     [Fact] public void AutomationControlledExit_QueuesNativeQuitAfterPublicCommand()
     {
         var source = File.ReadAllText(Path.Combine(ProjectRoot, "src", "PRecAnnot.Plant3D2026", "FirstLimitedApplyAutomation.cs"));