init: 数字员工平台初始代码

包含前端（Vue3 + VueFlow 画布）、后端（Go）、文档体系。
- 工作台画布：节点拖放、连线模式、右键菜单、AI 助手
- 后端：连接器 API、专员种子数据
- 导航：左侧导航、工坊、市场、控制台

eai_ap_app/backend-go/internal/api/certificate.go

@@ -0,0 +1,69 @@
+package api
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/gin-gonic/gin"
+
+	"eaisalestrain/backend/internal/middleware"
+	"eaisalestrain/backend/internal/model"
+	"eaisalestrain/backend/internal/store"
+	"eaisalestrain/backend/internal/web"
+)
+
+// issueCertificate 正式考试通过后颁发证书（幂等：同一 exam_record 只发一张）。
+func issueCertificate(u *model.User, rec model.ExamRecord) {
+	if u == nil || !rec.Passed {
+		return
+	}
+	var n int64
+	store.DB.Model(&model.Certificate{}).Where("exam_record_id = ?", rec.ID).Count(&n)
+	if n > 0 {
+		return
+	}
+	certNo := fmt.Sprintf("BST-%06d", rec.ID)
+	store.DB.Create(&model.Certificate{
+		UserID: u.ID, ExamRecordID: rec.ID, UserName: u.FullName,
+		ExamName: rec.ExamName, Score: rec.Score, TotalScore: rec.TotalScore, PassScore: rec.PassScore,
+		CertNo: certNo, IssuedAt: time.Now(),
+	})
+}
+
+// MyCertificates GET /api/exam/certificates —— 我的证书列表
+func MyCertificates(c *gin.Context) {
+	u := middleware.CurrentUser(c)
+	if u == nil {
+		web.Fail(c, web.NewAuthError("未登录"))
+		return
+	}
+	var items []model.Certificate
+	store.DB.Where("user_id = ?", u.ID).Order("issued_at DESC").Find(&items)
+	web.OK(c, items)
+}
+
+// CertificateDetail GET /api/exam/certificates/{id} —— 证书详情（本人或管理员可看，用于打印留存）
+func CertificateDetail(c *gin.Context) {
+	u := middleware.CurrentUser(c)
+	id, ok := parseID(c, "id")
+	if !ok {
+		return
+	}
+	var cert model.Certificate
+	if err := store.DB.First(&cert, id).Error; err != nil {
+		web.Fail(c, web.NewNotFoundError("证书不存在"))
+		return
+	}
+	if u == nil || (u.Role != "admin" && cert.UserID != u.ID) {
+		web.Fail(c, web.NewForbiddenError("无权查看他人证书"))
+		return
+	}
+	web.OK(c, cert)
+}
+
+// AdminCertificates GET /api/system/certificates —— 全员证书（管理员）
+func AdminCertificates(c *gin.Context) {
+	var items []model.Certificate
+	store.DB.Order("issued_at DESC").Find(&items)
+	web.OK(c, items)
+}