Implement present box

Signed-off-by: Sean Du <do4suki@gmail.com>

internal/handler/reward/sellunit.go

@@ -0,0 +1,29 @@
+package reward
+
+import (
+	"honoka-chan/internal/constant"
+	"honoka-chan/internal/middleware"
+	"honoka-chan/internal/router"
+	commonschema "honoka-chan/internal/schema/common"
+	rewardschema "honoka-chan/internal/schema/reward"
+	"honoka-chan/internal/session"
+
+	"github.com/gin-gonic/gin"
+)
+
+func sellUnit(ctx *gin.Context) {
+	ss := session.Get(ctx)
+	defer ss.Finalize()
+
+	ss.Respond(rewardschema.SellUnitResp{
+		ResponseData: commonschema.ErrorData{
+			ErrorCode: constant.ErrorCodeNoUnitIsSellable,
+		},
+		ReleaseInfo: []any{},
+		StatusCode:  600,
+	})
+}
+
+func init() {
+	router.AddHandler("main.php", "POST", "/reward/sellUnit", middleware.Common, sellUnit)
+}