feat: expand masks, structural filters, and solution similarity dedupe

StatusReporter.cs

@@ -0,0 +1,63 @@
+using System;
+using System.Diagnostics;
+using System.Text;
+
+internal sealed class StatusReporter
+{
+    private int _dotCounter = 0;
+    private string _lastMessage = string.Empty;
+    private DateTime _lastWriteTime = DateTime.MinValue;
+
+    public void Show(string message, bool withDots = false)
+    {
+        if (withDots)
+        {
+            _dotCounter++;
+            message = $"{message}{Dots()}";
+        }
+        Write(message, newline: false);
+    }
+
+    public string Dots()
+    {
+        var dots = (_dotCounter % 3) + 1;
+        return new string('.', dots);
+    }
+
+    public void ShowLine(string message)
+    {
+        Write(message, newline: true);
+    }
+
+    private void Write(string message, bool newline)
+    {
+        if (_lastMessage == message && !newline) return;
+        var now = DateTime.UtcNow;
+        if (!newline && (now - _lastWriteTime).TotalMilliseconds < 200)
+        {
+            return;
+        }
+        _lastWriteTime = now;
+        var pad = string.Empty;
+        _lastMessage = message;
+        var output = $"\r\u001b[K{message}{pad}";
+        if (newline)
+        {
+            Console.Error.WriteLine(output);
+            _lastMessage = string.Empty;
+        }
+        else
+        {
+            Console.Error.Write(output);
+        }
+    }
+
+    public static string FormatDuration(TimeSpan elapsed)
+    {
+        if (elapsed.TotalMinutes >= 1)
+        {
+            return $"{(int)elapsed.TotalMinutes}m {elapsed.Seconds}s";
+        }
+        return $"{elapsed.Seconds}s";
+    }
+}