Created C# projects

SudokuSolver/Program.cs

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+// See https://aka.ms/new-console-template for more information
+Console.WriteLine("Hello, World!");

SudokuSolver/SudokuSolver.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>