feat: add NuGet and Godot distribution

DotNet~/Runtime/ShrinkDataSaverRuntime.cs

@@ -0,0 +1,43 @@
+#nullable enable
+
+using System.IO;
+using Cysharp.Threading.Tasks;
+using ShrinkSDK.Runtime;
+
+namespace ShrinkDataSaver;
+
+public sealed class ShrinkDataSaverRuntimeConfig
+{
+    public string? RootPath { get; set; }
+    public string SaveFileExtension { get; set; } = ".sav";
+    public string SettingsFileName { get; set; } = "settings.json";
+    public int CurrentSaveVersion { get; set; } = 1;
+    public int MaxSlots { get; set; } = 3;
+    public float SettingsWriteDebounceSeconds { get; set; } = 0.35f;
+    public bool DontDestroyOnLoadDriver { get; set; }
+}
+
+public static class ShrinkDataSaverRuntime
+{
+    public static bool IsInitialized { get; private set; }
+
+    public static void Initialize(ShrinkDataSaverRuntimeConfig? config = null)
+    {
+        if (IsInitialized) return;
+        config ??= new ShrinkDataSaverRuntimeConfig();
+        var root = string.IsNullOrWhiteSpace(config.RootPath)
+            ? ShrinkRuntimeServices.Paths.PersistentDataPath
+            : config.RootPath!;
+        Directory.CreateDirectory(root);
+        var storage = new LocalStorageProvider(root);
+        ShrinkDataSaverPlatform.SettingsWriteDebounceSeconds = config.SettingsWriteDebounceSeconds;
+        ShrinkDataSaverPlatform.MaxSlots = config.MaxSlots;
+        ShrinkSettings.Initialize(storage, Path.Combine(root, config.SettingsFileName));
+        ShrinkSave.Initialize(storage, Path.Combine(root, "saves"), config.SaveFileExtension,
+            config.CurrentSaveVersion);
+        ShrinkSettings.LoadAsync().Forget();
+        IsInitialized = true;
+        ShrinkRuntimeServices.Logger.Log(ShrinkLogLevel.Information,
+            $"[ShrinkDataSaver] Runtime initialized. Root: {root}");
+    }
+}

DotNet~/ShrinkSDK.DataSaver.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>netstandard2.1</TargetFramework>
+    <EnableDefaultCompileItems>false</EnableDefaultCompileItems>
+    <AssemblyName>ShrinkDataSaver.Runtime</AssemblyName>
+    <RootNamespace>ShrinkDataSaver</RootNamespace>
+    <PackageId>ShrinkSDK.DataSaver</PackageId>
+    <Version>2.3.0</Version>
+    <Description>ShrinkSDK engine-neutral versioned save and settings runtime.</Description>
+    <ShrinkCodeGenEnabled>false</ShrinkCodeGenEnabled>
+    <Nullable>disable</Nullable>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="Runtime\ShrinkDataSaverRuntime.cs" />
+    <Compile Include="..\Runtime\AssemblyInfo.cs" />
+    <Compile Include="..\Runtime\DataSerializer.cs" />
+    <Compile Include="..\Runtime\IStorageProvider.cs" />
+    <Compile Include="..\Runtime\LocalStorageProvider.cs" />
+    <Compile Include="..\Runtime\MigrationChain.cs" />
+    <Compile Include="..\Runtime\SaveEncryptor.cs" />
+    <Compile Include="..\Runtime\SaveTypes.cs" />
+    <Compile Include="..\Runtime\ShrinkDataSaverPlatform.cs" />
+    <Compile Include="..\Runtime\ShrinkSave.cs" />
+    <Compile Include="..\Runtime\ShrinkSettings.cs" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
+    <PackageReference Include="UniTask" Version="2.5.10" />
+    <PackageReference Include="ShrinkSDK.Runtime.Abstractions" Version="0.1.0" />
+  </ItemGroup>
+</Project>