修复余额不足仍可启动充电问题

统一启动金额优先级并在启动前校验会员余额。

同步完成订单创建和余额支付后再返回鉴权成功，并增加支付凭证补偿、异常停机和结算保护。

jsowell-admin/src/test/java/com/jsowell/pile/util/ChargeAmountUtilsTest.java

@@ -0,0 +1,33 @@
+package com.jsowell.pile.util;
+
+import com.jsowell.common.constant.Constants;
+import org.junit.jupiter.api.Test;
+
+import java.math.BigDecimal;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ChargeAmountUtilsTest {
+
+    @Test
+    void resolveStartupAmount_shouldPreferFrontendAmount() {
+        BigDecimal amount = ChargeAmountUtils.resolveStartupAmount(
+                new BigDecimal("100"), new BigDecimal("300"));
+
+        assertEquals(new BigDecimal("100"), amount);
+    }
+
+    @Test
+    void resolveStartupAmount_shouldUseMemberDefaultWhenFrontendAmountIsNull() {
+        BigDecimal amount = ChargeAmountUtils.resolveStartupAmount(null, new BigDecimal("300"));
+
+        assertEquals(new BigDecimal("300"), amount);
+    }
+
+    @Test
+    void resolveStartupAmount_shouldUseCodeDefaultWhenOtherAmountsAreUnavailable() {
+        BigDecimal amount = ChargeAmountUtils.resolveStartupAmount(null, BigDecimal.ZERO);
+
+        assertEquals(Constants.BALANCE_PAY_MAX_AMOUNT_NEW, amount);
+    }
+}