Added Meld diff application as a diff program

src/Assent/Reporters/DiffPrograms/MeldDiffProgram.cs

@@ -0,0 +1,34 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Assent.Reporters.DiffPrograms;
+
+public class MeldDiffProgram : DiffProgramBase
+{
+    static readonly IReadOnlyList<string> DefaultSearchPaths;
+
+    static MeldDiffProgram()
+    {
+        var paths = new List<string>();
+        if (DiffReporter.IsWindows)
+        {
+            paths.AddRange(WindowsProgramFilePaths
+                .Select(p => $@"{p}\Meld\Meld.exe")
+                .ToArray());
+        }
+        else
+        {
+            paths.Add("/usr/bin/meld");
+            paths.Add("/usr/local/bin/meld");
+            paths.Add("/snap/bin/meld");
+            paths.Add("/opt/homebrew/bin/meld");
+        }
+        DefaultSearchPaths = paths;
+    }
+
+    public MeldDiffProgram()
+        : base(DefaultSearchPaths) { }
+
+    protected override string CreateProcessStartArgs(string receivedFile, string approvedFile) => "\"" + receivedFile + "\" \"" + approvedFile + "\"";
+}
+

src/Assent/Reporters/DiffReporter.cs

@@ -24,13 +24,15 @@ static DiffReporter()
                     new KDiff3DiffProgram(),
                     new XdiffDiffProgram(),
                     new P4MergeDiffProgram(),
-                    new VsCodeDiffProgram()
+                    new VsCodeDiffProgram(),
+                    new MeldDiffProgram()
                 }
                 : new IDiffProgram[]
                 {
                     new EnvironmentVariableDiffProgram(),
                     new BeyondCompareDiffProgram(),
-                    new VsCodeDiffProgram()
+                    new VsCodeDiffProgram(),
+                    new MeldDiffProgram()
                 };
 
         }