refactor(api): 升级 trading-service API 前缀至 v2

将 trading-service 的 API 版本从 v1 升级到 v2，统一 2.0 系统架构：

**trading-service:**
- main.ts: 全局前缀 api/v1 → api/v2
- Dockerfile: 健康检查路径 /api/v1/health → /api/v2/health
- transfer.service.ts: 更新调用 mining-service 的 API 路径
  - /api/v1/mining/accounts/.../transfer-out → /api/v2/...
  - /api/v1/mining/accounts/.../transfer-in → /api/v2/...

此变更使 trading-service 正式成为 2.0 系统的一部分，
与 auth-service、contribution-service、mining-service、
mining-admin-service、mining-wallet-service 保持一致。

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

backend/services/trading-service/Dockerfile

@@ -45,6 +45,6 @@ ENV TZ=Asia/Shanghai
 EXPOSE 3022
 
 HEALTHCHECK --interval=30s --timeout=10s --start-period=60s --retries=3 \
-    CMD curl -f http://localhost:3022/api/v1/health || exit 1
+    CMD curl -f http://localhost:3022/api/v2/health || exit 1
 
 CMD ["/app/start.sh"]

backend/services/trading-service/src/application/services/transfer.service.ts

@@ -184,7 +184,7 @@ export class TransferService {
     transferNo: string,
   ): Promise<{ success: boolean; txId?: string; message?: string }> {
     try {
-      const response = await fetch(`${this.miningServiceUrl}/api/v1/mining/accounts/${accountSequence}/transfer-out`, {
+      const response = await fetch(`${this.miningServiceUrl}/api/v2/mining/accounts/${accountSequence}/transfer-out`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ amount, transferNo }),
@@ -203,7 +203,7 @@ export class TransferService {
     transferNo: string,
   ): Promise<{ success: boolean; txId?: string; message?: string }> {
     try {
-      const response = await fetch(`${this.miningServiceUrl}/api/v1/mining/accounts/${accountSequence}/transfer-in`, {
+      const response = await fetch(`${this.miningServiceUrl}/api/v2/mining/accounts/${accountSequence}/transfer-in`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ amount, transferNo }),

backend/services/trading-service/src/main.ts

@@ -20,7 +20,7 @@ async function bootstrap() {
     credentials: true,
   });
 
-  app.setGlobalPrefix('api/v1');
+  app.setGlobalPrefix('api/v2');
 
   const config = new DocumentBuilder()
     .setTitle('Trading Service API')