Handle Vault 109 quest handoff

When the local player leaves COVault109, the plugin now completes MQ101 and starts MQ102 at stage 10 on the game thread, with a log entry for confirmation. Updated the changelog and architecture/dev-log docs to reflect the new Vault 109 flow, and refreshed the compiled Creation Kit script artifact.

plugin/src/main.cpp

@@ -13,6 +13,7 @@
 #include "RE/B/BIPED_OBJECT.h"
 #include "RE/B/BipedAnim.h"
 #include "RE/B/BSFixedString.h"
+#include "RE/C/Console.h"
 #include "RE/I/IAnimationGraphManagerHolder.h"
 #include "RE/P/PipboyManager.h"
 #include "RE/P/PipboyMenu.h"
@@ -647,6 +648,16 @@ namespace
 		}
 	}
 
+	void AdvanceMainQuestAfterVault109Exit()
+	{
+		RE::Console::ExecuteCommand("completequest MQ101");
+		RE::Console::ExecuteCommand("startquest MQ102");
+		RE::Console::ExecuteCommand("setstage MQ102 10");
+
+		LogInfoWithLocalPlayerPrefix(
+			"Player left COVault109; completed MQ101 (0001ED86) and started MQ102 (0001CC2A) at stage 10.");
+	}
+
 	void PollLocalPlayerTransform()
 	{
 		auto* player = TryGetLocalPlayer();
@@ -717,6 +728,9 @@ namespace
 
 		if (soloCellTransformSuppressed) {
 			LogInfoWithLocalPlayerPrefix("Local player left solo cell; transform packet sending resumed.");
+			if (hasLastTransform && lastKnownLocation.isSoloCell && !currentLocation.isSoloCell) {
+				AdvanceMainQuestAfterVault109Exit();
+			}
 			soloCellTransformSuppressed = false;
 		}