feat(docker): Gracefully reload Caddy configuration

CaddyManager.Contracts/Docker/CaddyReloadResponse.cs

@@ -0,0 +1,17 @@
+namespace CaddyManager.Contracts.Docker;
+
+/// <summary>
+/// Result of a graceful Caddy configuration reload
+/// </summary>
+public class CaddyReloadResponse
+{
+    /// <summary>
+    /// Indicates whether Caddy accepted and applied the configuration
+    /// </summary>
+    public bool Success { get; set; }
+
+    /// <summary>
+    /// Output from Caddy when the reload failed, typically the configuration validation error
+    /// </summary>
+    public string Message { get; set; } = string.Empty;
+}