feat: model expert catalog categories

backend/internal/models/ai_expert_category.go

@@ -0,0 +1,17 @@
+package models
+
+import "time"
+
+// SenlinAgentAIExpertCategory groups experts from the local expert catalog.
+type SenlinAgentAIExpertCategory struct {
+	ID        uint   `gorm:"primaryKey"`
+	Identity  string `gorm:"type:char(36);uniqueIndex"`
+	Slug      string `gorm:"size:80;uniqueIndex;not null"`
+	Name      string `gorm:"size:120;not null"`
+	CreatedAt time.Time
+	UpdatedAt time.Time
+}
+
+func (SenlinAgentAIExpertCategory) TableName() string {
+	return "senlin_agent_ai_expert_categories"
+}