feat: 添加 seed.go 初始化文件 — 默认用户+审批流程+系统设置

- seedDefaultUsers: 4个默认用户(admin/dba/auditor/developer, 密码admin123)
- seedDefaultWorkflow: 默认审批流程(提交→DBA审核→执行)
- seedDefaultSettings: 数据脱敏默认配置
- 所有操作幂等，已有数据不覆盖
- main.go调用seedAll()统一初始化

backend/cmd/server/seed.go

@@ -0,0 +1,116 @@
+package main
+
+import (
+	"log"
+
+	"sql-platform/internal/model"
+
+	"golang.org/x/crypto/bcrypt"
+	"gorm.io/gorm"
+)
+
+// seedAll initializes the database with default data (idempotent).
+// Safe to run on every startup — skips existing records.
+func seedAll(db *gorm.DB) {
+	seedDefaultUsers(db)
+	seedDefaultWorkflow(db)
+	seedDefaultSettings(db)
+	log.Println("[seed] Default data initialized")
+}
+
+// seedDefaultUsers creates default users if they don't exist.
+func seedDefaultUsers(db *gorm.DB) {
+	type seedUser struct {
+		username    string
+		displayName string
+		email       string
+		role        string
+		password    string
+		active      bool
+	}
+	users := []seedUser{
+		{"admin", "超级管理员", "admin@opsx.local", "admin", "admin123", true},
+		{"dba", "DBA管理员", "dba@opsx.local", "dba", "admin123", true},
+		{"auditor", "审计员", "auditor@opsx.local", "auditor", "admin123", true},
+		{"developer", "开发者", "developer@opsx.local", "developer", "admin123", true},
+	}
+
+	for _, u := range users {
+		var existing model.User
+		if db.Where("username = ?", u.username).First(&existing).Error != nil {
+			hash, _ := bcrypt.GenerateFromPassword([]byte(u.password), bcrypt.DefaultCost)
+			email := u.email
+			active := u.active
+			user := model.User{
+				Username:       u.username,
+				DisplayName:    u.displayName,
+				Email:          &email,
+				HashedPassword: string(hash),
+				Role:           u.role,
+				IsActive:       &active,
+			}
+			if err := db.Create(&user).Error; err != nil {
+				log.Printf("[seed] Failed to create user %s: %v", u.username, err)
+			} else {
+				log.Printf("[seed] Created user: %s (%s)", u.username, u.role)
+			}
+		}
+	}
+}
+
+// seedDefaultWorkflow creates a default approval workflow if none exists.
+func seedDefaultWorkflow(db *gorm.DB) {
+	var count int64
+	db.Model(&model.WorkflowDefinition{}).Count(&count)
+	if count > 0 {
+		return // Already has workflows
+	}
+
+	// Create default workflow
+	t := true
+	wf := model.WorkflowDefinition{
+		Name:        "默认审批流程",
+		Description: strPtr("系统默认审批流程：开发者提交 → DBA审核 → 执行"),
+		IsDefault:   &t,
+		IsActive:    &t,
+	}
+	if err := db.Create(&wf).Error; err != nil {
+		log.Printf("[seed] Failed to create default workflow: %v", err)
+		return
+	}
+
+	// Create steps
+	steps := []model.WorkflowStep{
+		{
+			WorkflowID:   wf.ID,
+			StepNumber:   1,
+			Name:         "提交审核",
+			StepType:     "submit",
+			IsRequired:   &t,
+			TimeoutHours: intPtr(0),
+		},
+		{
+			WorkflowID:   wf.ID,
+			StepNumber:   2,
+			Name:         "DBA审核",
+			StepType:     "audit",
+			ApproverRole: strPtr("dba"),
+			IsRequired:   &t,
+			TimeoutHours: intPtr(24),
+		},
+		{
+			WorkflowID:   wf.ID,
+			StepNumber:   3,
+			Name:         "执行变更",
+			StepType:     "execute",
+			IsRequired:   &t,
+			TimeoutHours: intPtr(0),
+		},
+	}
+	for _, s := range steps {
+		db.Create(&s)
+	}
+	log.Printf("[seed] Created default workflow: %s (id=%d)", wf.Name, wf.ID)
+}
+
+func intPtr(v int) *int { return &v }