feat(mobile-next): 迁移 Android 一对一语音通话薄适配与入口

复用官方 OpenIMLive 信令与房间，换票改走账号服务 /api/rtc_token；入口仅音频，占线/超时/重复回调与销毁释放由公司层防护。

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

mobile-next/lib/pages/chat/chat_view.dart

@@ -225,7 +225,7 @@ class ChatPage extends StatelessWidget {
                 onCloseMultiModel: logic.exit,
                 onClickMoreBtn: logic.chatSetup,
                 onClickCallBtn: logic.call,
-                showCallBtn: FeatureFlags.livekitCall,
+                showCallBtn: FeatureFlags.livekitCall && logic.isSingleChat,
               ),
               body: SafeArea(
                 child: WaterMarkBgView(
@@ -244,7 +244,7 @@ class ChatPage extends StatelessWidget {
                     toolbox: ChatToolBox(
                       onTapAlbum: logic.onTapAlbum,
                       onTapCamera: logic.onTapCamera,
-                      onTapCall: logic.call,
+                      onTapCall: FeatureFlags.livekitCall && logic.isSingleChat ? logic.call : null,
                       onTapCard: logic.onTapCarte,
                       onTapFile: logic.onTapFile,
                       onTapLocation: logic.onTapLocation,