fix: convert YOLO PT to ONNX opset 12 for OpenCV 4.6 compatibility

internal/captcha/handler.go

@@ -35,9 +35,9 @@ var modelConfigs = map[string]struct {
 	"Rotation-RotNetR.onnx":  {remote: "[AntiCAP]-Rotation-RotNetR.onnx", optional: false},
 	"Siamese-ResNet18.onnx":  {remote: "[AntiCAP]-Siamese-ResNet18.onnx", optional: false},
 	"CharSets.txt":           {remote: "[Dddd]-CharSets.txt", optional: false},
-	// Detection 模型需要 OpenCV 4.8+ 支持，暂标记为可选
-	"Detection_Icon.onnx":    {remote: "Detection_Icon.onnx", optional: true},
-	"Detection_Text.onnx":    {remote: "Detection_Text.onnx", optional: true},
+	// Detection 模型已转换为 opset 12，兼容 OpenCV 4.6
+	"Detection_Icon.onnx":    {remote: "Detection_Icon.onnx", optional: false},
+	"Detection_Text.onnx":    {remote: "Detection_Text.onnx", optional: false},
 }
 
 // 从 Gitea 仓库下载（公开仓库，无需认证）
@@ -96,11 +96,11 @@ func (h *Handler) loadModels() {
 		}
 	}
 
-	// 加载 YOLO 检测模型（需要 OpenCV 4.8+）
+	// 加载 YOLO 检测模型（opset 12 兼容 OpenCV 4.6）
 	iconPath := filepath.Join(h.modelPath, "Detection_Icon.onnx")
 	if _, err := os.Stat(iconPath); err == nil {
 		if err := opencv.LoadYOLO("icon", iconPath, ""); err != nil {
-			fmt.Printf("提示: Icon 检测模型加载失败 (需要 OpenCV 4.8+): %v\n", err)
+			fmt.Printf("警告: 加载 Icon 检测模型失败: %v\n", err)
 		} else {
 			fmt.Println("Icon 检测模型加载成功")
 		}
@@ -109,7 +109,7 @@ func (h *Handler) loadModels() {
 	textPath := filepath.Join(h.modelPath, "Detection_Text.onnx")
 	if _, err := os.Stat(textPath); err == nil {
 		if err := opencv.LoadYOLO("text", textPath, ""); err != nil {
-			fmt.Printf("提示: Text 检测模型加载失败 (需要 OpenCV 4.8+): %v\n", err)
+			fmt.Printf("警告: 加载 Text 检测模型失败: %v\n", err)
 		} else {
 			fmt.Println("Text 检测模型加载成功")
 		}