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/src/config.js

@@ -76,6 +76,15 @@ function getConfig() {
     tencentSecretId: process.env.TENCENT_SECRET_ID ?? "",
     tencentSecretKey: process.env.TENCENT_SECRET_KEY ?? "",
     tencentOcrRegion: process.env.TENCENT_OCR_REGION ?? "ap-beijing",
+
+    emailEnabled: process.env.EMAIL_ENABLED === "true",
+    emailFrom: process.env.EMAIL_FROM ?? "[email protected]",
+    emailBaseUrl: process.env.EMAIL_BASE_URL ?? "",
+    smtpHost: process.env.SMTP_HOST ?? "",
+    smtpPort: Number(process.env.SMTP_PORT ?? 587),
+    smtpSecure: process.env.SMTP_SECURE === "true",
+    smtpUser: process.env.SMTP_USER ?? "",
+    smtpPass: process.env.SMTP_PASS ?? "",
   };
 }