chore: initialize standalone UPM package

Runtime/ShrinkCommandAppComponent.cs

@@ -0,0 +1,49 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using Cysharp.Threading.Tasks;
+using ShrinkApp;
+using ShrinkContext;
+using ShrinkCommand;
+
+namespace ShrinkCommand.Integration.App
+{
+    /// <summary>
+    /// ShrinkCommand 的原生 Cordis 组件（阶段 3）：
+    /// 提供 <c>shrink.service.command</c> 余效应键（默认命令服务），依赖者按键注入；
+    /// 与经典 ShrinkCommandAppInstaller（ModuleId "shrink.command"）二选一使用（同键供给冲突保护）。
+    /// </summary>
+    public sealed class ShrinkCommandAppComponent : IShrinkComponent
+    {
+        public const string ServiceKey = "shrink.service.command";
+        public const string ModuleKey = "app.module.shrink.command";
+
+        private static readonly string[] ProvideKeys = { ModuleKey, ServiceKey };
+
+        public string Name => "shrink.command";
+
+        public IReadOnlyList<string> Inject => Array.Empty<string>();
+
+        public IReadOnlyList<string> Provide => ProvideKeys;
+
+        public UniTask ApplyAsync(ShrinkCtx ctx, object? config)
+        {
+            var service = ShrinkCommandRuntime.Default;
+            ctx.Set(ServiceKey, service);
+            ctx.Set(ModuleKey, Name);
+
+            if (config is ShrinkAppServices appServices)
+            {
+                var facade = new ShrinkCommandAppService(service);
+                appServices.Register(facade);
+                ctx.EffectInverse(() =>
+                {
+                    appServices.TryUnregister(facade);
+                    return UniTask.CompletedTask;
+                });
+            }
+
+            return UniTask.CompletedTask;
+        }
+    }
+}