feat(ai): add local expert library

backend/internal/models/ai_expert.go

@@ -0,0 +1,26 @@
+package models
+
+import "time"
+
+// SenlinAgentAIExpert 是本地专家库中的可选 AI 角色。
+type SenlinAgentAIExpert struct {
+	ID            uint   `gorm:"primaryKey"`
+	Identity      string `gorm:"type:char(36);uniqueIndex"`
+	Slug          string `gorm:"size:160;uniqueIndex;not null"`
+	Category      string `gorm:"size:80;index;not null"`
+	CategoryName  string `gorm:"size:120;not null"`
+	Name          string `gorm:"size:160;index;not null"`
+	Description   string `gorm:"type:text;not null"`
+	Emoji         string `gorm:"size:32"`
+	Color         string `gorm:"size:32"`
+	SystemPrompt  string `gorm:"type:text;not null"`
+	Source        string `gorm:"size:255;not null"`
+	SourceLicense string `gorm:"size:32;not null"`
+	Enabled       bool   `gorm:"not null;default:true;index"`
+	CreatedAt     time.Time
+	UpdatedAt     time.Time
+}
+
+func (SenlinAgentAIExpert) TableName() string {
+	return "senlin_agent_ai_experts"
+}