feat(materials): add campaign materials overlay for sessions

Let GMs manage and show images over the scene from the editor and control panel, with zoom tools, help docs, and full ru/en i18n.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/main/windows/createWindows.editorClose.test.ts

@@ -39,11 +39,19 @@ void test('createWindows: окно описания сцены закрывае
   const src = readCreateWindows();
   assert.ok(src.includes('openSceneDescriptionWindow'));
   assert.ok(src.includes('closeSceneDescriptionWindow'));
-  assert.ok(src.includes("createWindow('sceneDescription')"));
+  assert.ok(src.includes("createWindow('sceneDescription'"));
   assert.match(src, /export function closeMultiWindow[\s\S]*closeSceneDescriptionWindow/);
   assert.match(src, /kind !== 'presentation' && kind !== 'control'[\s\S]*closeSceneDescriptionWindow/);
 });
 
+void test('createWindows: окно материалов закрывается с multi-window', () => {
+  const src = readCreateWindows();
+  assert.ok(src.includes('openMaterialsWindow'));
+  assert.ok(src.includes('closeMaterialsWindow'));
+  assert.ok(src.includes("createWindow('materials'"));
+  assert.match(src, /export function closeMultiWindow[\s\S]*closeMaterialsWindow/);
+});
+
 void test('createWindows: production — loadFile для HTML (не только file://)', () => {
   const src = readCreateWindows();
   assert.ok(src.includes('loadFile'));