added support for modpack defined in version descriptor

Mlaumcherb.Client.Avalonia/холопы/HashHelper.cs

@@ -0,0 +1,32 @@
+using System.Security.Cryptography;
+using DTLib.Extensions;
+
+namespace Mlaumcherb.Client.Avalonia.холопы;
+
+public static class HashHelper
+{
+    private static SHA1 _hasher;
+
+    static HashHelper()
+    {
+        _hasher = SHA1.Create();
+    }
+
+    public static string HashFileSHA1(IOPath f)
+    {
+        using var fs = File.OpenRead(f);
+        byte[] hash = _hasher.ComputeHash(fs);
+        return hash.HashToString();
+    }
+
+    public static bool CheckFileSHA1(IOPath f, string? sha1, bool checkHash)
+    {
+        if (!File.Exists(f))
+            return false;
+        
+        if(checkHash)
+            return sha1 is not null && HashFileSHA1(f) == sha1;
+
+        return true;
+    }
+}

Mlaumcherb.Client.Avalonia/холопы/PathHelper.cs

@@ -54,4 +54,10 @@ public static class PathHelper
     
     public static IOPath GetLog4jConfigFilePath() =>
         Path.Concat(GetAssetsDir(), GetLog4jConfigFileName());
+
+    public static IOPath GetModpackDescriptorPath(string game_version) => 
+        Path.Concat(GetVersionDir(game_version), "timerix_modpack.json");
+    
+    public static IOPath GetModpackManifestPath(string game_version) => 
+        Path.Concat(GetVersionDir(game_version), "timerix_modpack_files.json");
 }