feat(M05-B): 完成微信支付退款与对账基础

backend/src/config.ts

@@ -17,6 +17,7 @@ const configSchema = z.object({
   QIPAI_SESSION_TTL_SECONDS: z.coerce.number().int().min(300).max(2592000).default(604800),
   QIPAI_WECHAT_APP_SECRETS: z.string().default('{}'),
   QIPAI_TEST_PAYMENT_ENABLED: z.enum(['true', 'false']).default('false'),
+  QIPAI_WECHAT_PAY_CREDENTIALS: z.string().default('{}'),
   QIPAI_MQTT_URL: z.string().url().default('mqtt://101.42.38.246:1883'),
   QIPAI_MQTT_USERNAME: z.string().default(''),
   QIPAI_MQTT_PASSWORD: z.string().default('')
@@ -56,7 +57,8 @@ export function loadConfig(env: NodeJS.ProcessEnv = process.env) {
     },
     payment: {
       testAdapterEnabled: parsed.NODE_ENV !== 'production'
-        && parsed.QIPAI_TEST_PAYMENT_ENABLED === 'true'
+        && parsed.QIPAI_TEST_PAYMENT_ENABLED === 'true',
+      wechatCredentialsJson: parsed.QIPAI_WECHAT_PAY_CREDENTIALS
     },
     mqtt: {
       url: parsed.QIPAI_MQTT_URL,