chore(unity): 固定Unity CLI Loop本地包并移除UnitySkills依赖

Client/Packages/io.github.hatayama.uloopmcp/Editor/Server/ServerShutdownReason.cs

@@ -0,0 +1,21 @@
+namespace io.github.hatayama.uLoopMCP
+{
+    /// <summary>
+    /// Reason for server shutdown, sent to TypeScript MCP server for message differentiation.
+    /// Values must match TypeScript ServerShutdownReason constants.
+    /// </summary>
+    public enum ServerShutdownReason
+    {
+        /// <summary>
+        /// Server is shutting down due to domain reload (compilation).
+        /// TypeScript side should show "waiting" message.
+        /// </summary>
+        DomainReload,
+
+        /// <summary>
+        /// Server is shutting down due to editor quit.
+        /// TypeScript side should show "server not running" error.
+        /// </summary>
+        EditorQuit
+    }
+}