feat(configmanager): add AutoDiscoveryService with tests

Add service for auto-discovering configuration file locations. The
service searches in prioritized order:
1. JDESCOPING_CONFIG_PATH environment variable
2. Same directory as executable
3. ../JdeScoping.Host/ relative to executable
4. User config directory (~/.jdescoping on Unix, %LOCALAPPDATA%\JdeScoping on Windows)

Includes 9 unit tests covering all search locations, priority order,
edge cases (missing directory, missing appsettings.json), and
cancellation token support.

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

@@ -0,0 +1,86 @@
+using Microsoft.Extensions.Logging;
+
+namespace JdeScoping.ConfigManager.Services;
+
+/// <summary>
+/// Service for auto-discovering configuration file locations.
+/// Searches in prioritized order:
+/// 1. JDESCOPING_CONFIG_PATH environment variable
+/// 2. Same directory as executable
+/// 3. ../JdeScoping.Host/ relative to executable
+/// 4. User config directory (~/.jdescoping on Unix, %LOCALAPPDATA%\JdeScoping on Windows)
+/// </summary>
+public class AutoDiscoveryService : IAutoDiscoveryService
+{
+    private readonly IFileSystem _fileSystem;
+    private readonly ILogger<AutoDiscoveryService>? _logger;
+    private const string EnvVarName = "JDESCOPING_CONFIG_PATH";
+    private const string AppSettingsFileName = "appsettings.json";
+
+    public AutoDiscoveryService(IFileSystem fileSystem, ILogger<AutoDiscoveryService>? logger = null)
+    {
+        _fileSystem = fileSystem;
+        _logger = logger;
+    }
+
+    public Task<string?> FindConfigFolderAsync(CancellationToken ct = default)
+    {
+        // 1. Check environment variable
+        var envPath = Environment.GetEnvironmentVariable(EnvVarName);
+        if (!string.IsNullOrEmpty(envPath) && IsValidConfigFolder(envPath))
+        {
+            _logger?.LogInformation("Found config folder from environment variable: {Path}", envPath);
+            return Task.FromResult<string?>(envPath);
+        }
+
+        // 2. Check same directory as executable
+        var exeDir = AppContext.BaseDirectory;
+        if (IsValidConfigFolder(exeDir))
+        {
+            _logger?.LogInformation("Found config folder in executable directory: {Path}", exeDir);
+            return Task.FromResult<string?>(exeDir);
+        }
+
+        // 3. Check ../JdeScoping.Host/ relative to executable
+        var hostDir = _fileSystem.Combine(exeDir, "..", "JdeScoping.Host");
+        if (IsValidConfigFolder(hostDir))
+        {
+            _logger?.LogInformation("Found config folder in host directory: {Path}", hostDir);
+            return Task.FromResult<string?>(hostDir);
+        }
+
+        // 4. Check user config directory
+        var userConfigDir = GetUserConfigDirectory();
+        if (userConfigDir != null && IsValidConfigFolder(userConfigDir))
+        {
+            _logger?.LogInformation("Found config folder in user directory: {Path}", userConfigDir);
+            return Task.FromResult<string?>(userConfigDir);
+        }
+
+        _logger?.LogWarning("Could not find config folder in any standard location");
+        return Task.FromResult<string?>(null);
+    }
+
+    private bool IsValidConfigFolder(string path)
+    {
+        if (!_fileSystem.DirectoryExists(path))
+            return false;
+
+        var appSettingsPath = _fileSystem.Combine(path, AppSettingsFileName);
+        return _fileSystem.FileExists(appSettingsPath);
+    }
+
+    private string? GetUserConfigDirectory()
+    {
+        if (OperatingSystem.IsWindows())
+        {
+            var localAppData = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
+            return _fileSystem.Combine(localAppData, "JdeScoping");
+        }
+        else
+        {
+            var home = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
+            return _fileSystem.Combine(home, ".jdescoping");
+        }
+    }
+}

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

@@ -0,0 +1,19 @@
+namespace JdeScoping.ConfigManager.Services;
+
+/// <summary>
+/// Service for auto-discovering configuration file locations.
+/// </summary>
+public interface IAutoDiscoveryService
+{
+    /// <summary>
+    /// Searches for a configuration folder containing appsettings.json.
+    /// Search order:
+    /// 1. JDESCOPING_CONFIG_PATH environment variable
+    /// 2. Same directory as executable
+    /// 3. ../JdeScoping.Host/ relative to executable
+    /// 4. User config directory (~/.jdescoping on Unix, %LOCALAPPDATA%\JdeScoping on Windows)
+    /// </summary>
+    /// <param name="ct">Cancellation token.</param>
+    /// <returns>The path to the config folder, or null if not found.</returns>
+    Task<string?> FindConfigFolderAsync(CancellationToken ct = default);
+}