docs: add XML documentation and ConfigManager implementation plans

Add comprehensive XML documentation (param/returns tags) across 132 source
files to improve IntelliSense and API discoverability. Include ConfigManager
design documents and implementation plans for phases 1-9.

NEW/src/Utils/JdeScoping.ConfigManager/Services/IConfigFileService.cs

@@ -7,8 +7,35 @@ namespace JdeScoping.ConfigManager.Services;
 /// </summary>
 public interface IConfigFileService
 {
+    /// <summary>
+    /// Loads the application settings configuration from the specified file path.
+    /// </summary>
+    /// <param name="path">The file path to load appsettings from.</param>
+    /// <param name="ct">Cancellation token for the operation.</param>
+    /// <returns>The loaded configuration model or a new empty model if deserialization fails.</returns>
     Task<ConfigModel> LoadAppSettingsAsync(string path, CancellationToken ct = default);
+
+    /// <summary>
+    /// Loads the pipelines configuration from the specified file path.
+    /// </summary>
+    /// <param name="path">The file path to load pipelines from.</param>
+    /// <param name="ct">Cancellation token for the operation.</param>
+    /// <returns>The loaded pipelines configuration model or a new empty model if deserialization fails.</returns>
     Task<PipelinesConfigModel> LoadPipelinesAsync(string path, CancellationToken ct = default);
+
+    /// <summary>
+    /// Saves the application settings configuration to the specified file path.
+    /// </summary>
+    /// <param name="path">The file path to save appsettings to.</param>
+    /// <param name="config">The configuration model to save.</param>
+    /// <param name="ct">Cancellation token for the operation.</param>
     Task SaveAppSettingsAsync(string path, ConfigModel config, CancellationToken ct = default);
+
+    /// <summary>
+    /// Saves the pipelines configuration to the specified file path.
+    /// </summary>
+    /// <param name="path">The file path to save pipelines to.</param>
+    /// <param name="config">The pipelines configuration model to save.</param>
+    /// <param name="ct">Cancellation token for the operation.</param>
     Task SavePipelinesAsync(string path, PipelinesConfigModel config, CancellationToken ct = default);
 }