fix: 在 seed 中添加 GENESIS 系统种子用户

问题原因：
- seed.ts 会删除所有 userAccount 记录
- 即使 migration 创建了 GENESIS 用户，seed 运行后也会被删除
- 之前的系统账户使用 userId 1-4，但 GENESIS 应该是 userId 1

解决方案：
- 将 GENESIS 用户添加到 SYSTEM_ACCOUNTS 数组
- userId: 1, accountSequence: 'SYSTEM00001', referralCode: 'GENESIS'
- 其他系统账户的 userId 顺延到 2-5

系统账户列表：
- userId 1: GENESIS (系统种子用户，用于注册推荐码)
- userId 2: 总部社区 (HQ000001)
- userId 3: 成本费账户 (COST0002)
- userId 4: 运营费账户 (OPER0003)
- userId 5: RWAD底池账户 (POOL0004)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/services/identity-service/prisma/seed.ts

@@ -23,27 +23,34 @@ const ADMIN_ACCOUNTS = [
 const SYSTEM_ACCOUNTS = [
   {
     userId: BigInt(1),
+    accountSequence: 'SYSTEM00001',  // 系统种子用户（用于注册推荐码）
+    nickname: '系统',
+    referralCode: 'GENESIS',
+    status: 'ACTIVE',
+  },
+  {
+    userId: BigInt(2),
     accountSequence: 'S0000000001',  // 总部社区
     nickname: '总部社区',
     referralCode: 'HQ000001',
     status: 'SYSTEM',
   },
   {
-    userId: BigInt(2),
+    userId: BigInt(3),
     accountSequence: 'S0000000002',  // 成本费账户
     nickname: '成本费账户',
     referralCode: 'COST0002',
     status: 'SYSTEM',
   },
   {
-    userId: BigInt(3),
+    userId: BigInt(4),
     accountSequence: 'S0000000003',  // 运营费账户
     nickname: '运营费账户',
     referralCode: 'OPER0003',
     status: 'SYSTEM',
   },
   {
-    userId: BigInt(4),
+    userId: BigInt(5),
     accountSequence: 'S0000000004',  // RWAD底池账户
     nickname: 'RWAD底池账户',
     referralCode: 'POOL0004',
@@ -114,7 +121,7 @@ async function main() {
 
   console.log('Database seeded successfully!');
   console.log(`- Initialized account sequence generator for date ${dateKey}`);
-  console.log(`- Created ${SYSTEM_ACCOUNTS.length} system accounts (S0000000001-S0000000004)`);
+  console.log(`- Created ${SYSTEM_ACCOUNTS.length} system accounts (including GENESIS seed user)`);
   console.log(`- Created ${ADMIN_ACCOUNTS.length} admin accounts`);
 }