feat: 公开宿主组合加载 API、Forge 风格依赖版本区间与加载顺序、程序集解析策略

- ShrinkModComponentDiscovery.Discover 公开：只发现、不执行生命周期
- ShrinkModLoader.LoadComposed / ShrinkModCordisRuntime.ApplyComposedAsync：宿主提供元数据组合加载，支持纯数据包与 IShrinkModWrapper 公开真实实例
- 公开 TryAttachEventBusInstance，随生命周期逆操作释放
- 依赖新增 VersionRange（Maven/Forge 区间语法）与 Ordering（Before/After）
- AssemblyResolvePolicy 可限制跨模组程序集解析

Tools~/HostTests/Tests/EditorTestShim.cs

@@ -0,0 +1,55 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text.RegularExpressions;
+using NUnit.Framework;
+using UnityEngine;
+
+namespace UnityEditor.PackageManager
+{
+    public class PackageInfo
+    {
+        public string resolvedPath;
+        public static PackageInfo FindForAssembly(System.Reflection.Assembly assembly)
+        {
+            var directory = new DirectoryInfo(AppContext.BaseDirectory);
+            while (directory != null && !File.Exists(Path.Combine(directory.FullName, "package.json"))) directory = directory.Parent;
+            return new PackageInfo { resolvedPath = directory?.FullName ?? throw new DirectoryNotFoundException("Package root") };
+        }
+    }
+}
+namespace UnityEditor
+{
+    public static class AssetDatabase
+    {
+        public static string[] FindAssets(string query) => Array.Empty<string>();
+        public static string GUIDToAssetPath(string guid) => guid;
+    }
+}
+namespace UnityEngine.TestTools
+{
+    public static class LogAssert
+    {
+        internal static readonly Queue<(LogType type, Regex text)> Expected = new();
+        public static void Expect(LogType type, Regex text) => Expected.Enqueue((type, text));
+        public static void Expect(LogType type, string text) => Expect(type, new Regex(Regex.Escape(text)));
+    }
+}
+[SetUpFixture]
+public class LogVerification
+{
+    private readonly List<string> _unexpected = new();
+    [OneTimeSetUp] public void Start() => Debug.Logged += Observe;
+    private void Observe(LogType type, string text)
+    {
+        var expected = UnityEngine.TestTools.LogAssert.Expected;
+        if (expected.Count > 0 && expected.Peek().type == type && expected.Peek().text.IsMatch(text)) expected.Dequeue();
+        else if (type == LogType.Error || type == LogType.Exception) _unexpected.Add(text);
+    }
+    [OneTimeTearDown] public void Finish()
+    {
+        Debug.Logged -= Observe;
+        Assert.IsEmpty(_unexpected, "Unexpected Unity-style errors");
+        Assert.IsEmpty(UnityEngine.TestTools.LogAssert.Expected, "Expected log was not emitted");
+    }
+}