Stabilize WebGL flip reveal handoff

public/js/loader.js

@@ -24,7 +24,7 @@ const ModuleState = {
     ERROR: 'ERROR'
 };
 
-const MODULE_CACHE_BUSTER = '20260610-book-timeline-j';
+const MODULE_CACHE_BUSTER = '20260610-book-timeline-l';
 window.MODULE_CACHE_BUSTER = MODULE_CACHE_BUSTER;
 
 /**
@@ -830,17 +830,17 @@ const ModuleLoader = (function() {
     async function completeFinalization() {
         isLoadingComplete = true;
 
-        // Call the start method on the game loop module directly
-        // Ensure the game loop module was found during initialization
+        // Call the start method on the game loop module directly.
+        // Starting before hiding the overlay lets socket connection and
+        // save/resume state settle as part of the loader handoff.
         if (gameLoopModule && typeof gameLoopModule.start === 'function') {
-             // Hide the overlay first, then start the game loop
-            await hideOverlay();
-            console.log("Loader: Overlay hidden, starting Game Loop.");
             try {
-                gameLoopModule.start();
+                console.log("Loader: Starting Game Loop before hiding overlay.");
+                await gameLoopModule.start();
             } catch (error) {
                 console.error("Error starting Game Loop:", error);
             }
+            await hideOverlay();
         } else {
             console.error("Loader: Game Loop module not found or start method missing.");
             // Hide overlay anyway, but log error