优化自动拾取的预处理环节，优化最终文字展现，使自动拾取OCR识别更加稳定 (#2211)

BetterGenshinImpact/GameTask/AutoPick/TextRectExtractor.cs

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+using System;
+using System.Linq;
+
+namespace BetterGenshinImpact.GameTask.AutoPick;
+
+using OpenCvSharp;
+
+public static class TextRectExtractor
+{
+    /// <summary>
+    /// 从图片中提取文字范围（假定文字从最左边贴边开始，向右连续）
+    /// 结果矩形固定 x=0,y=0,h=原图高度，只计算连续文字宽度。
+    /// </summary>
+    public static Rect GetTextBoundingRect(Mat textMat, out Mat bin)
+    {
+        // 转换为灰度图
+        Mat gray = new Mat();
+        if (textMat.Channels() == 3)
+        {
+            Cv2.CvtColor(textMat, gray, ColorConversionCodes.BGR2GRAY);
+        }
+        else
+        {
+            gray = textMat.Clone();
+        }
+
+        // 使用阈值160进行二值化处理
+        bin = new Mat();
+        Cv2.Threshold(gray, bin, 160, 255, ThresholdTypes.Binary);
+
+        // 形态学操作：先腐蚀后膨胀，去除噪点并保持文字完整
+        Mat kernel = Cv2.GetStructuringElement(MorphShapes.Rect, new Size(3, 3));
+        Cv2.Erode(bin, bin, kernel, iterations: 1);
+        Cv2.Dilate(bin, bin, kernel, iterations: 2);
+        kernel.Dispose();
+        gray.Dispose();
+        return ProjectionRect(textMat, bin);
+    }
+
+    private static Rect ProjectionRect(Mat textMat, Mat bin)
+    {
+        // 投影：对行做 ReduceSum，得到 1 x width 的列和
+        using var projection = new Mat();
+        Cv2.Reduce(bin, projection, 0, ReduceTypes.Sum, MatType.CV_32S);
+        int width = projection.Cols;
+        projection.GetArray(out int[] colSums);
+
+        int maxGap = 30; // 允许的最大连续空列数
+        int gapCount = 0;
+        int lastNonEmpty = -1;
+
+        for (int x = 0; x < width; x++)
+        {
+            bool hasInk = colSums[x] > 0;
+            if (hasInk)
+            {
+                lastNonEmpty = x;
+                gapCount = 0;
+            }
+            else
+            {
+                gapCount++;
+                if (gapCount > maxGap)
+                {
+                    break;
+                }
+            }
+        }
+        
+        if (lastNonEmpty == -1)
+        {
+            // 没有检测到文字
+            return new Rect();
+        }
+
+        Rect boundingRect = new Rect(0, 0, lastNonEmpty, textMat.Height);
+        return boundingRect;
+    }
+}