feat: Add Learn-Number tool for preschool math practice and refactor HTML components

cmd/toolbox/main.go

@@ -11,6 +11,7 @@ import (
 	"os"
 	"strconv"
 	"toolbox/pkg/base"
+	_ "toolbox/pkg/learnnumber"
 	_ "toolbox/pkg/zitie" // 匿名导入以触发 init()
 
 	"github.com/gin-gonic/gin"
@@ -55,8 +56,8 @@ func main() {
 	r.StaticFS("/static", http.FS(subFS))
 
 	// 3. 模板引擎初始化
-	// 关键修复：先 Sub 再 Parse，确保路径匹配
-	tmpl, err := template.ParseFS(subFS, "layout.html", "index.html")
+	// 递归加载 web 目录下所有的 .html 文件
+	tmpl, err := template.ParseFS(subFS, "layout.html", "index.html", "tools/*.html")
 	if err != nil {
 		log.Fatalf("Failed to parse templates: %v", err)
 	}