fix: seedRoleMenus adds missing menus + SSE error display

- seedRoleMenus now adds new menu items to existing roles
- AIChatPage shows SSE error messages in assistant bubble

backend/internal/svc/servicecontext.go

@@ -353,13 +353,6 @@ func seedRoleMenus(db *gorm.DB) {
 	}
 
 	for _, r := range roles {
-		// 检查角色是否已有菜单关联
-		var count int64
-		db.Model(&model.RoleMenu{}).Where("role_id = ?", r.Id).Count(&count)
-		if count > 0 {
-			continue
-		}
-
 		var menuIds []int64
 		switch r.Code {
 		case model.RoleSuperAdmin, model.RoleAdmin:
@@ -368,12 +361,23 @@ func seedRoleMenus(db *gorm.DB) {
 			menuIds = defaultMenuIds
 		}
 
-		if len(menuIds) > 0 {
-			records := make([]model.RoleMenu, 0, len(menuIds))
-			for _, menuId := range menuIds {
-				records = append(records, model.RoleMenu{RoleId: r.Id, MenuId: menuId})
+		// 获取已有的菜单关联
+		var existingMenuIds []int64
+		db.Model(&model.RoleMenu{}).Where("role_id = ?", r.Id).Pluck("menu_id", &existingMenuIds)
+		existingSet := make(map[int64]bool)
+		for _, id := range existingMenuIds {
+			existingSet[id] = true
+		}
+
+		// 添加缺失的菜单关联
+		var newRecords []model.RoleMenu
+		for _, menuId := range menuIds {
+			if !existingSet[menuId] {
+				newRecords = append(newRecords, model.RoleMenu{RoleId: r.Id, MenuId: menuId})
 			}
-			db.Create(&records)
+		}
+		if len(newRecords) > 0 {
+			db.Create(&newRecords)
 		}
 	}
 	log.Println("[Seed] RoleMenus seeded successfully")

frontend/react-shadcn/pc/src/pages/AIChatPage.tsx

@@ -148,7 +148,12 @@ export function AIChatPage() {
       for await (const chunk of stream) {
         try {
           const parsed = JSON.parse(chunk)
-          if (parsed.content) {
+          if (parsed.error) {
+            accumulated = `Error: ${parsed.error}`
+            setMessages(prev => prev.map(m =>
+              m.id === assistantMsg.id ? { ...m, content: accumulated, isStreaming: false } : m
+            ))
+          } else if (parsed.content) {
             accumulated += parsed.content
             setMessages(prev => prev.map(m =>
               m.id === assistantMsg.id ? { ...m, content: accumulated } : m