🐛 fix(copilot): pass correct scope when creating new session in PageEditor (#11714)

The switchTopic function was called without scope parameter, defaulting to 'main' scope while PageAgentProvider uses 'page' scope, causing new session creation to fail.

fix LOBE-3378

src/features/PageEditor/Copilot/Toolbar.tsx

@@ -189,7 +189,7 @@ const CopilotToolbar = memo<CopilotToolbarProps>(({ agentId, isHovered }) => {
           <div className={cx(styles.fadeContainer, isHovered ? styles.fadeIn : styles.fadeOut)}>
             <ActionIcon
               icon={PlusIcon}
-              onClick={() => switchTopic()}
+              onClick={() => switchTopic(null, { scope: 'page' })}
               size={DESKTOP_HEADER_ICON_SIZE}
               title={t('actions.addNewTopic')}
             />

src/styles/antdOverride.ts

@@ -1,3 +1,4 @@
+import { isDesktop } from '@lobechat/const';
 import { type Theme, css } from 'antd-style';
 import { rgba } from 'polished';
 
@@ -16,4 +17,12 @@ export default ({ token }: { prefixCls: string; token: Theme }) => css`
     background: ${rgba(token.colorBgLayout, 0.5)} !important;
     backdrop-filter: blur(2px);
   }
+
+  ${isDesktop &&
+  css`
+    .${token.prefixCls}-modal-mask.${token.prefixCls}-modal-mask-blur {
+      background: ${rgba(token.colorBgLayout, 0.8)} !important;
+      backdrop-filter: none !important;
+    }
+  `}
 `;