feat(mobile-next): 工号登录与目录薄适配，并完成登录/会话/聊天/通讯录第一批界面

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

mobile-next/openim_common/lib/src/widgets/chat/chat_bubble.dart

@@ -34,7 +34,7 @@ class ChatBubble extends StatelessWidget {
         alignment: alignment,
         decoration: BoxDecoration(
           color:
-              backgroundColor ?? (isISend ? Styles.c_CCE7FE : Styles.c_F4F5F7),
+              backgroundColor ?? (isISend ? Styles.c_CCE7FE : Styles.c_FFFFFF),
           borderRadius: borderRadius(isISend),
         ),
         child: child,

mobile-next/openim_common/lib/src/widgets/chat/chat_item_view.dart

@@ -13,12 +13,7 @@ double pictureWidth = 120.w;
 double videoWidth = 120.w;
 double locationWidth = 220.w;
 
-BorderRadius borderRadius(bool isISend) => BorderRadius.only(
-      topLeft: Radius.circular(isISend ? 6.r : 0),
-      topRight: Radius.circular(isISend ? 0 : 6.r),
-      bottomLeft: Radius.circular(6.r),
-      bottomRight: Radius.circular(6.r),
-    );
+BorderRadius borderRadius(bool isISend) => BorderRadius.circular(8.r);
 
 class MsgStreamEv<T> {
   final String id;