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

pkg/learnnumber/tool.go

@@ -0,0 +1,48 @@
+package learnnumber
+
+import (
+	"fmt"
+	"net/http"
+	"toolbox/pkg/base"
+	"toolbox/pkg/learnnumber/logic"
+
+	"github.com/gin-gonic/gin"
+)
+
+type learnNumberTool struct{}
+
+func init() {
+	base.Register(&learnNumberTool{})
+}
+
+func (t *learnNumberTool) ID() string          { return "learn-number" }
+func (t *learnNumberTool) Name() string        { return "幼儿数学助手" }
+func (t *learnNumberTool) Description() string { return "包含数图形、基础加减法等趣味数学练习" }
+
+func (t *learnNumberTool) Init() error {
+	fmt.Println("Initializing Learn-Number tool...")
+	return nil
+}
+
+func (t *learnNumberTool) RegisterRoutes(r *gin.RouterGroup) {
+	r.POST("/counting", t.handleCounting)
+}
+
+func (t *learnNumberTool) handleCounting(c *gin.Context) {
+	var req logic.CountingRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	if req.TotalCount <= 0 { req.TotalCount = 20 }
+	if req.TotalCount > 30 { req.TotalCount = 30 }
+
+	pdfBytes, err := logic.GenerateCountingPDF(req)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.Data(http.StatusOK, "application/pdf", pdfBytes)
+}