Rename viewer bundles .js -> .mjs so they stop leaking into the main realm

ComfyUI auto-imports every web/**/*.js into the shared main page; the four
big bundles (three, vtk-gltf, viewer-bundle-vtk, gsplat) only ever run
inside the viewer iframes but were getting pulled into the main document
too, where they wrote window.THREE / window.vtk / globalThis.* and could
collide with any other 3D pack. The **/*.js glob only matches .js, so
renaming to .mjs drops them from the auto-import while the iframes still
load them via classic <script src> (mime resolves to text/javascript).
window.* pollution from these bundles is gone from the main realm.

javascript/viewer_dual.html

@@ -350,7 +350,7 @@
         </div>
     </div>
 
-    <script src="./js/vtk-gltf.js"></script>
+    <script src="./js/vtk-gltf.mjs"></script>
 
     <script>
         // Get VTK.js classes

javascript/viewer_dual_slider.html

@@ -341,8 +341,8 @@
         </label>
     </div>
 
-    <script src="./js/vtk-gltf.js"></script>
-    <script src="./js/viewer-bundle-vtk.js"></script>
+    <script src="./js/vtk-gltf.mjs"></script>
+    <script src="./js/viewer-bundle-vtk.mjs"></script>
 
     <script>
         // Get VTK.js classes

javascript/viewer_dual_textured.html

@@ -330,7 +330,7 @@
         </div>
     </div>
 
-    <script src="./js/vtk-gltf.js"></script>
+    <script src="./js/vtk-gltf.mjs"></script>
 
     <script>
         // Get VTK.js classes

javascript/viewer_fbx.html

@@ -146,10 +146,10 @@
 
     <!--
     Load bundled Three.js and all dependencies.
-    The bundle is expected at ../js/viewer-bundle-three.js relative to this HTML file.
+    The bundle is expected at ../js/viewer-bundle-three.mjs relative to this HTML file.
     When copied by prestartup_script.py, the directory structure should be:
       web/viewer_fbx.html
-      web/js/viewer-bundle-three.js
+      web/js/viewer-bundle-three.mjs
     -->
     <script>
         // Dynamically determine the bundle path based on how this HTML is loaded
@@ -171,7 +171,7 @@
 
             // Create script element to load the bundle
             var bundleScript = document.createElement('script');
-            bundleScript.src = baseUrl + 'js/viewer-bundle-three.js';
+            bundleScript.src = baseUrl + 'js/viewer-bundle-three.mjs';
             bundleScript.onload = function() {
                 console.log('[FBX Viewer] Three.js bundle loaded from:', bundleScript.src);
                 initViewer();

javascript/viewer_fbx_compare.html

@@ -293,7 +293,7 @@
             }
 
             var bundleScript = document.createElement('script');
-            bundleScript.src = baseUrl + 'js/viewer-bundle-three.js';
+            bundleScript.src = baseUrl + 'js/viewer-bundle-three.mjs';
             bundleScript.onload = function() {
                 console.log('[UniRig Compare] Three.js bundle loaded');
                 initViewer();

javascript/viewer_fbx_debug.html

@@ -439,7 +439,7 @@
             }
 
             var bundleScript = document.createElement('script');
-            bundleScript.src = baseUrl + 'js/viewer-bundle-three.js';
+            bundleScript.src = baseUrl + 'js/viewer-bundle-three.mjs';
             bundleScript.onload = function() {
                 console.log('[FBX Debug Viewer] Three.js bundle loaded from:', bundleScript.src);
                 initViewer();

javascript/viewer_gaussian.html

@@ -133,7 +133,7 @@
     </div>
 
     <!-- Load bundled gsplat.js -->
-    <script src="./js/gsplat-bundle.js"></script>
+    <script src="./js/gsplat-bundle.mjs"></script>
 
     <script type="module">
         // Use the globally exported GSPLAT

javascript/viewer_multi.html

@@ -297,7 +297,7 @@
         </div>
     </div>
 
-    <script src="./js/vtk-gltf.js"></script>
+    <script src="./js/vtk-gltf.mjs"></script>
 
     <script>
         // Get VTK.js classes

javascript/viewer_multi_slider.html

@@ -81,8 +81,8 @@
         <button id="resetSlider">Reset Sliders</button>
     </div>
 
-    <script src="./js/vtk-gltf.js"></script>
-    <script src="./js/viewer-bundle-vtk.js"></script>
+    <script src="./js/vtk-gltf.mjs"></script>
+    <script src="./js/viewer-bundle-vtk.mjs"></script>
 
     <script>
         const vtkFullScreenRenderWindow = vtk.Rendering.Misc.vtkFullScreenRenderWindow;

javascript/viewer_slicer.html

@@ -16,7 +16,7 @@
         button.active { background: #2c5d8a; border-color: #4a90c0; }
         button:hover { background: #444; }
     </style>
-    <script src="./js/vtk-gltf.js"></script>
+    <script src="./js/vtk-gltf.mjs"></script>
 </head>
 <body>
 <div id="wrap">

javascript/viewer_vtk.html

@@ -151,9 +151,9 @@
     </div>
 
     <!-- Load VTK.js bundle -->
-    <script src="./js/vtk-gltf.js"></script>
+    <script src="./js/vtk-gltf.mjs"></script>
     <!-- Load unified viewer bundle -->
-    <script src="./js/viewer-bundle-vtk.js"></script>
+    <script src="./js/viewer-bundle-vtk.mjs"></script>
 
     <script>
         // Use unified viewer modules

javascript/viewer_vtk_textured.html

@@ -96,9 +96,9 @@
     </div>
 
     <!-- Load VTK.js bundle with GLTFImporter support -->
-    <script src="./js/vtk-gltf.js"></script>
+    <script src="./js/vtk-gltf.mjs"></script>
     <!-- Load unified viewer bundle -->
-    <script src="./js/viewer-bundle-vtk.js"></script>
+    <script src="./js/viewer-bundle-vtk.mjs"></script>
 
     <script>
         // Use the unified viewer module