fix(family): 昵称全空格按空处理，命名回退到我的家庭

cfc-backend/src/main/java/com/etotem/cfc/util/FamilyNamingSupport.java

@@ -10,6 +10,9 @@ public final class FamilyNamingSupport {
             return user.getRealName().trim() + "家庭";
         }
         String nickname = user.getNickname();
-        return (nickname != null && !nickname.isEmpty()) ? nickname + "的家庭" : "我的家庭";
+        if (nickname != null && !nickname.trim().isEmpty()) {
+            return nickname.trim() + "的家庭";
+        }
+        return "我的家庭";
     }
 }

cfc-backend/src/test/java/com/etotem/cfc/unit/FamilyNamingSupportTest.java

@@ -16,4 +16,5 @@ public class FamilyNamingSupportTest {
     @Test void realName空_回退昵称() { assertEquals("昵称的家庭", FamilyNamingSupport.buildFamilyName(user("", "昵称"))); }
     @Test void realName全空格_回退昵称() { assertEquals("昵称的家庭", FamilyNamingSupport.buildFamilyName(user("   ", "昵称"))); }
     @Test void 都空_我的家庭() { assertEquals("我的家庭", FamilyNamingSupport.buildFamilyName(user(null, null))); }
+    @Test void nickname全空格_我的家庭() { assertEquals("我的家庭", FamilyNamingSupport.buildFamilyName(user(null, "   "))); }
 }