feat(server): 完成 F15 邮件通知（SMTP/Nodemailer）\n\n- 新增 email 服务（EMAIL_ENABLED + SMTP_* 配置）\n- 待办/审批/付款/密码重置触发可选邮件，失败降级不阻塞\n- 更新 server/README 邮件配置说明，并推进 CSV 状态为 DONE

server/package-lock.json

@@ -23,6 +23,7 @@
         "fastify": "^5.7.4",
         "fastify-plugin": "^5.1.0",
         "node-cron": "^4.2.1",
+        "nodemailer": "^6.10.1",
         "pg": "^8.18.0",
         "prisma": "^7.3.0",
         "tencentcloud-sdk-nodejs": "^4.1.14",
@@ -1934,6 +1935,15 @@
       "integrity": "sha512-g9yhqoedzIUm0nTnTqAQvueMPVOuIY16bqgAJJC8XOOubYFNwz6IER9qs0Gq2Xd0+CecCKFjtdDTMA4u4xG06Q==",
       "license": "MIT"
     },
+    "node_modules/nodemailer": {
+      "version": "6.10.1",
+      "resolved": "https://registry.npmjs.org/nodemailer/-/nodemailer-6.10.1.tgz",
+      "integrity": "sha512-Z+iLaBGVaSjbIzQ4pX6XV41HrooLsQ10ZWPUehGmuantvzWoDVBnmsdUcOIDM1t+yPor5pDhVlDESgOMEGxhHA==",
+      "license": "MIT-0",
+      "engines": {
+        "node": ">=6.0.0"
+      }
+    },
     "node_modules/nypm": {
       "version": "0.6.4",
       "resolved": "https://registry.npmjs.org/nypm/-/nypm-0.6.4.tgz",