test(backend): switchToMember 测试 body 类型改为 Map<String, Object>

与 /api/family/member/switch 控制器签名同步：前端发送
{memberId, source: "family_member"}，source 是 String，
Map<String, Long> 会导致 Jackson 反序列化失败。其他端点
（kick / editable / logs）不接收 source，保持 Map<String, Long>。

cfc-backend/src/test/java/com/etotem/cfc/controller/family/FamilyMembersControllerTest.java

@@ -115,7 +115,7 @@ public class FamilyMembersControllerTest {
     @Test
     public void switchToMember_Success() {
         Long userId = 1L;
-        Map<String, Long> body = new HashMap<>();
+        Map<String, Object> body = new HashMap<>();
         body.put("memberId", 2L);
 
         SwitchMemberVO vo = new SwitchMemberVO();
@@ -131,7 +131,7 @@ public class FamilyMembersControllerTest {
     @Test
     public void switchToMember_MissingMemberId() {
         Long userId = 1L;
-        Map<String, Long> body = new HashMap<>();
+        Map<String, Object> body = new HashMap<>();
 
         Result<SwitchMemberVO> result = controller.switchToMember(body, userId);
         assertEquals(500, result.getCode());

cfc-backend/src/test/java/com/etotem/cfc/integration/FamilyMemberManagementFlowTest.java

@@ -200,7 +200,7 @@ public class FamilyMemberManagementFlowTest {
     @DisplayName("[场景5] 切换到成员视角 - 期望返回切换凭证并正确设置上下文")
     void parentSwitchesToMemberView_Success() {
         // === Given：选择了要切换的成员 ===
-        Map<String, Long> switchRequest = new HashMap<>();
+        Map<String, Object> switchRequest = new HashMap<>();
         switchRequest.put("memberId", CHILD_MEMBER_ID);
 
         SwitchMemberVO mockSwitchVO = new SwitchMemberVO();
@@ -231,7 +231,7 @@ public class FamilyMemberManagementFlowTest {
     @DisplayName("[场景5b] 切换到本人视角 - 期望返回错误提示")
     void parentSwitchesToSelf_Fails() {
         // === Given：选择了自己的用户ID作为成员ID ===
-        Map<String, Long> switchRequest = new HashMap<>();
+        Map<String, Object> switchRequest = new HashMap<>();
         switchRequest.put("memberId", PARENT_USER_ID); // 自己的用户ID
 
         when(familyMemberService.switchToMember(PARENT_USER_ID, PARENT_USER_ID))