fix(backend): 后台注册限流配置优先并保留注入兜底

docs/api-phase1.md

@@ -125,7 +125,10 @@ app.register.max-per-ip-per-day
 app.register.max-per-device-per-day
 ```
 
-键缺失或值不是整数时回退默认 5 / 3；值小于等于 0 表示对应维度不限制。
+运行时优先读取 `sys_config`。键缺失或值不是整数时，回退 `application.yml`
+中的 `fruitshorts.auth.register-max-per-ip-per-day` /
+`fruitshorts.auth.register-max-per-device-per-day`，缺省为 5 / 3；
+值小于等于 0 表示对应维度不限制。
 开发种子配置为 0 / 0，生产建议恢复为 5 / 3。
 
 **残留风险**：IP 取自 `X-Forwarded-For`、设备号由客户端上报，都能伪造，只能挡脚本批量；

fruitshorts-app-api/src/main/resources/application.yml

@@ -43,6 +43,10 @@ springdoc:
     path: /v3/api-docs
 
 fruitshorts:
+  auth:
+    # 仅作 sys_config 缺失/非法时的兜底；运行时优先读取后台「系统配置」
+    register-max-per-ip-per-day: ${REGISTER_MAX_PER_IP_PER_DAY:5}
+    register-max-per-device-per-day: ${REGISTER_MAX_PER_DEVICE_PER_DAY:3}
   interaction:
     # MACHINE_FIRST：机审通过即发布，命中 REVIEW 级敏感词才转人工
     # PRE_REVIEW   ：全部先审后发（生产建议）

fruitshorts-app-api/src/test/java/com/fruitshorts/app/service/AppAuthServiceTest.java

@@ -26,6 +26,7 @@ import com.fruitshorts.user.vo.TokenRespVO;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.test.util.ReflectionTestUtils;
 
 import java.time.Duration;
 import java.time.LocalDateTime;
@@ -193,9 +194,9 @@ class AppAuthServiceTest {
 
     @Test
     void should_fallback_to_default_limit_when_config_is_not_numeric() {
-        setRegisterLimits(5, 3);
-        given(configService.get("app.register.max-per-ip-per-day", "5")).willReturn("invalid");
-        given(userMapper.selectCount(any())).willReturn(5L);
+        ReflectionTestUtils.setField(authService, "maxRegisterPerIpPerDay", 2);
+        given(configService.get("app.register.max-per-ip-per-day", "2")).willReturn("invalid");
+        given(userMapper.selectCount(any())).willReturn(2L);
 
         assertThatThrownBy(() -> authService.register(emailRegister("abcd1234", null), "203.0.113.8"))
                 .isInstanceOf(ServiceException.class)

fruitshorts-module-user/src/main/java/com/fruitshorts/user/service/AppAuthService.java

@@ -26,6 +26,7 @@ import com.fruitshorts.user.vo.LogoutReqVO;
 import com.fruitshorts.user.vo.RegisterReqVO;
 import com.fruitshorts.user.vo.TokenRespVO;
 import lombok.RequiredArgsConstructor;
+import org.springframework.beans.factory.annotation.Value;
 import org.springframework.dao.DuplicateKeyException;
 import org.springframework.security.crypto.password.PasswordEncoder;
 import org.springframework.stereotype.Service;
@@ -61,6 +62,14 @@ public class AppAuthService {
     private final PasswordEncoder passwordEncoder;
     private final ConfigService configService;
 
+    /** 后台 sys_config 缺失或非法时使用；小于等于 0 表示不限制。 */
+    @Value("${fruitshorts.auth.register-max-per-ip-per-day:5}")
+    private int maxRegisterPerIpPerDay = 5;
+
+    /** 后台 sys_config 缺失或非法时使用；小于等于 0 表示不限制。 */
+    @Value("${fruitshorts.auth.register-max-per-device-per-day:3}")
+    private int maxRegisterPerDevicePerDay = 3;
+
     @Transactional(rollbackFor = Exception.class)
     public TokenRespVO register(RegisterReqVO req, String clientIp) {
         String targetType = AppIdentifier.normalizeType(req.getTargetType());
@@ -305,8 +314,6 @@ public class AppAuthService {
 
     private static final String REGISTER_IP_LIMIT_KEY = "app.register.max-per-ip-per-day";
     private static final String REGISTER_DEVICE_LIMIT_KEY = "app.register.max-per-device-per-day";
-    private static final int DEFAULT_REGISTER_IP_LIMIT = 5;
-    private static final int DEFAULT_REGISTER_DEVICE_LIMIT = 3;
 
     private static final int PASSWORD_MIN_LENGTH = 8;
     private static final int PASSWORD_MAX_LENGTH = 64;
@@ -339,8 +346,8 @@ public class AppAuthService {
      */
     private void guardRegisterRisk(String clientIp, String deviceId) {
         LocalDateTime since = LocalDateTime.now().minusDays(1);
-        int ipLimit = registerLimit(REGISTER_IP_LIMIT_KEY, DEFAULT_REGISTER_IP_LIMIT);
-        int deviceLimit = registerLimit(REGISTER_DEVICE_LIMIT_KEY, DEFAULT_REGISTER_DEVICE_LIMIT);
+        int ipLimit = registerLimit(REGISTER_IP_LIMIT_KEY, maxRegisterPerIpPerDay);
+        int deviceLimit = registerLimit(REGISTER_DEVICE_LIMIT_KEY, maxRegisterPerDevicePerDay);
         String ip = AppIdentifier.nullSafe(clientIp);
         if (ipLimit > 0 && StringUtils.hasText(ip)) {
             Long byIp = appUserMapper.selectCount(Wrappers.<AppUser>lambdaQuery()