CUB-10: Create IMoonrakerClient interface and DTOs

- Expanded IMoonrakerClient interface with 6 strongly-typed methods:
  - GetServerInfoAsync (Moonraker /server/info)
  - IsReachableAsync (connectivity check)
  - GetPrinterInfoAsync (Moonraker /printer/info)
  - GetPrintHistoryAsync (Moonraker /server/history/items)
  - GetPrintStatsAsync (Moonraker /printer/objects/query?print_stats)
  - GetDisplayStatusAsync (Moonraker /printer/objects/query?display_status)
  - GetFilamentUsageAsync (retained for backward compatibility)

- Created Domain/DTOs/Moonraker/ with 7 DTOs:
  - MoonrakerServerInfo, MoonrakerPrinterInfo, MoonrakerPrintJob
  - MoonrakerHistoryResponse, MoonrakerPrintStats
  - MoonrakerDisplayStatus, MoonrakerRequest

- Updated MoonrakerClient implementation to support all new methods
  with proper JSON parsing and mapping helpers

- Full XML doc comments on all public members

backend/Domain/DTOs/Moonraker/MoonrakerDisplayStatus.cs

@@ -0,0 +1,19 @@
+namespace Extrudex.Domain.DTOs.Moonraker;
+
+/// <summary>
+/// Response DTO for Moonraker /printer/objects/query?display_status endpoint.
+/// Contains progress percentage and message for the current print job.
+/// Used by the SignalR hub to push real-time progress to connected clients.
+/// </summary>
+public class MoonrakerDisplayStatus
+{
+    /// <summary>
+    /// Print progress as a decimal between 0 and 1 (0% to 100%).
+    /// </summary>
+    public decimal Progress { get; set; }
+
+    /// <summary>
+    /// Status message displayed on the printer LCD (e.g., "Printing...", "Heating...").
+    /// </summary>
+    public string Message { get; set; } = string.Empty;
+}

backend/Domain/DTOs/Moonraker/MoonrakerHistoryResponse.cs

@@ -0,0 +1,20 @@
+namespace Extrudex.Domain.DTOs.Moonraker;
+
+/// <summary>
+/// Response DTO for the Moonraker /server/history/items endpoint.
+/// Wraps the paginated list of print job history items.
+/// </summary>
+public class MoonrakerHistoryResponse
+{
+    /// <summary>
+    /// The list of print job history items returned by Moonraker.
+    /// Most recent jobs appear first (descending by start time).
+    /// </summary>
+    public List<MoonrakerPrintJob> Items { get; set; } = [];
+
+    /// <summary>
+    /// Total number of print jobs available on the server
+    /// (for pagination; the Items list may be a subset).
+    /// </summary>
+    public int TotalCount { get; set; }
+}

backend/Domain/DTOs/Moonraker/MoonrakerPrintJob.cs

@@ -0,0 +1,56 @@
+namespace Extrudex.Domain.DTOs.Moonraker;
+
+/// <summary>
+/// Response DTO for a single Moonraker print job history item.
+/// Maps to the objects returned by /server/history/items.
+/// Contains filament usage, duration, and status for a completed or active print.
+/// </summary>
+public class MoonrakerPrintJob
+{
+    /// <summary>
+    /// Unique Moonraker job identifier (e.g., "000001").
+    /// </summary>
+    public string JobId { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Filename of the G-code file that was printed.
+    /// </summary>
+    public string Filename { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Current status of this print job: "completed", "cancelled", "error", "in_progress".
+    /// </summary>
+    public string Status { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Total filament used in millimeters for this print job.
+    /// This is the primary measurement; grams are derived from this value.
+    /// </summary>
+    public decimal FilamentUsedMm { get; set; }
+
+    /// <summary>
+    /// Total print duration in seconds.
+    /// </summary>
+    public decimal PrintDurationSeconds { get; set; }
+
+    /// <summary>
+    /// Total print duration including setup and warmup, in seconds.
+    /// </summary>
+    public decimal TotalDurationSeconds { get; set; }
+
+    /// <summary>
+    /// Timestamp when the print job started (UTC).
+    /// </summary>
+    public DateTime? StartTime { get; set; }
+
+    /// <summary>
+    /// Timestamp when the print job ended (UTC). Null if still in progress.
+    /// </summary>
+    public DateTime? EndTime { get; set; }
+
+    /// <summary>
+    /// Metadata dictionary from Moonraker. May contain filament_type,
+    /// filament_name, nozzle_diameter, and other slicer-provided fields.
+    /// </summary>
+    public Dictionary<string, object> Metadata { get; set; } = new();
+}

backend/Domain/DTOs/Moonraker/MoonrakerPrintStats.cs

@@ -0,0 +1,36 @@
+namespace Extrudex.Domain.DTOs.Moonraker;
+
+/// <summary>
+/// Response DTO for Moonraker /printer/objects/query?print_stats endpoint.
+/// Contains real-time print statistics including current job state,
+    /// filament consumed, and file being printed.
+/// </summary>
+public class MoonrakerPrintStats
+{
+    /// <summary>
+    /// Current print state: "standby", "printing", "paused", "complete", "error", "cancelled".
+    /// </summary>
+    public string State { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Total filament used in millimeters for the current print session.
+    /// </summary>
+    public decimal FilamentUsedMm { get; set; }
+
+    /// <summary>
+    /// Total print duration in seconds for the current print session.
+    /// </summary>
+    public decimal PrintDurationSeconds { get; set; }
+
+    /// <summary>
+    /// Filename of the G-code file currently being printed.
+    /// Null if no print is active.
+    /// </summary>
+    public string? Filename { get; set; }
+
+    /// <summary>
+    /// Detailed message from Klipper about the current print state.
+    /// May contain error details when state is "error".
+    /// </summary>
+    public string? Message { get; set; }
+}

backend/Domain/DTOs/Moonraker/MoonrakerPrinterInfo.cs

@@ -0,0 +1,26 @@
+namespace Extrudex.Domain.DTOs.Moonraker;
+
+/// <summary>
+/// Response DTO for the Moonraker /printer/info endpoint.
+/// Contains the current operational state of the Klipper printer.
+/// Used to determine whether the printer is idle, printing, paused, or in error.
+/// </summary>
+public class MoonrakerPrinterInfo
+{
+    /// <summary>
+    /// Current Klipper state: "ready", "startup", "shutdown", "error", "cancelled".
+    /// A "ready" state means the printer is connected and idle.
+    /// </summary>
+    public string State { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Detailed state message from Klipper. May contain error details
+    /// when the state is "error" or "shutdown".
+    /// </summary>
+    public string StateMessage { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Whether the Klipper firmware is currently connected and responsive.
+    /// </summary>
+    public bool KlippyReady { get; set; }
+}

backend/Domain/DTOs/Moonraker/MoonrakerRequest.cs

@@ -0,0 +1,25 @@
+namespace Extrudex.Domain.DTOs.Moonraker;
+
+/// <summary>
+/// Request DTO for querying the Moonraker API.
+/// Encapsulates the connection parameters needed to reach a specific
+/// Moonraker instance on a Klipper-based printer.
+/// </summary>
+public class MoonrakerRequest
+{
+    /// <summary>
+    /// Hostname or IP address of the Moonraker printer.
+    /// </summary>
+    public string HostnameOrIp { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Port number for the Moonraker API. Default: 7125.
+    /// </summary>
+    public int Port { get; set; } = 7125;
+
+    /// <summary>
+    /// Optional API key for authenticating with Moonraker.
+    /// Required when the server has API key authentication enabled.
+    /// </summary>
+    public string? ApiKey { get; set; }
+}

backend/Domain/DTOs/Moonraker/MoonrakerServerInfo.cs

@@ -0,0 +1,44 @@
+namespace Extrudex.Domain.DTOs.Moonraker;
+
+/// <summary>
+/// Response DTO for the Moonraker /server/info endpoint.
+/// Contains server identification and operational state.
+/// Used to verify connectivity and determine Moonraker version.
+/// </summary>
+public class MoonrakerServerInfo
+{
+    /// <summary>
+    /// The hostname of the Moonraker server (e.g., "mainsail").
+    /// </summary>
+    public string Hostname { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Moonraker software version string (e.g., "0.8.0-89ee464").
+    /// </summary>
+    public string SoftwareVersion { get; set; } = string.Empty;
+
+    /// <summary>
+    /// CPU model string reported by the host system.
+    /// </summary>
+    public string CpuInfo { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Whether Klipper is currently connected to the MCU.
+    /// </summary>
+    public bool KlippyConnected { get; set; }
+
+    /// <summary>
+    /// The current Klipper state (e.g., "ready", "startup", "error").
+    /// </summary>
+    public string KlippyState { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Whether the Moonraker API requires an authentication token.
+    /// </summary>
+    public bool ApiKeyRequired { get; set; }
+
+    /// <summary>
+    /// List of registered Moonraker plugin names.
+    /// </summary>
+    public List<string> Plugins { get; set; } = [];
+}

backend/Domain/Interfaces/IMoonrakerClient.cs

@@ -1,23 +1,26 @@
+using Extrudex.Domain.DTOs.Moonraker;
+
 namespace Extrudex.Domain.Interfaces;
 
 /// <summary>
 /// Client interface for communicating with Moonraker REST API endpoints
 /// on Klipper-based printers (e.g., Elegoo Centauri Carbon).
-/// Used to retrieve filament usage data, print job status, and
-/// remaining spool weight from the printer.
+/// Provides strongly-typed methods for server discovery, printer status,
+/// print job history, and real-time telemetry.
 /// </summary>
 public interface IMoonrakerClient
 {
     /// <summary>
-    /// Fetches the current filament usage data from the Moonraker server.
-    /// Returns a dictionary of usage metrics reported by the printer.
+    /// Checks whether the Moonraker server is reachable and responding.
+    /// Calls the /server/info endpoint and returns the server information
+    /// if successful, or null if the server is unreachable.
     /// </summary>
     /// <param name="hostnameOrIp">The printer's hostname or IP address.</param>
     /// <param name="port">The Moonraker API port (default: 7125).</param>
     /// <param name="apiKey">Optional API key for authentication.</param>
     /// <param name="cancellationToken">Cancellation token for the HTTP request.</param>
-    /// <returns>A dictionary of usage metric names to their decimal values.</returns>
-    Task<Dictionary<string, decimal>> GetFilamentUsageAsync(
+    /// <returns>Server info if reachable; <c>null</c> if unreachable.</returns>
+    Task<MoonrakerServerInfo?> GetServerInfoAsync(
         string hostnameOrIp,
         int port,
         string? apiKey,
@@ -25,6 +28,8 @@ public interface IMoonrakerClient
 
     /// <summary>
     /// Checks whether the Moonraker server is reachable and responding.
+    /// This is a convenience method equivalent to calling GetServerInfoAsync
+    /// and checking for a non-null result.
     /// </summary>
     /// <param name="hostnameOrIp">The printer's hostname or IP address.</param>
     /// <param name="port">The Moonraker API port (default: 7125).</param>
@@ -36,4 +41,91 @@ public interface IMoonrakerClient
         int port,
         string? apiKey,
         CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Fetches the current printer info from the /printer/info endpoint.
+    /// Returns the Klipper state and readiness status.
+    /// </summary>
+    /// <param name="hostnameOrIp">The printer's hostname or IP address.</param>
+    /// <param name="port">The Moonraker API port (default: 7125).</param>
+    /// <param name="apiKey">Optional API key for authentication.</param>
+    /// <param name="cancellationToken">Cancellation token for the HTTP request.</param>
+    /// <returns>Printer info if successful; <c>null</c> if the request failed.</returns>
+    Task<MoonrakerPrinterInfo?> GetPrinterInfoAsync(
+        string hostnameOrIp,
+        int port,
+        string? apiKey,
+        CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Fetches print job history from the /server/history/items endpoint.
+    /// Returns the most recent print jobs with filament usage data,
+    /// print duration, and completion status.
+    /// </summary>
+    /// <param name="hostnameOrIp">The printer's hostname or IP address.</param>
+    /// <param name="port">The Moonraker API port (default: 7125).</param>
+    /// <param name="apiKey">Optional API key for authentication.</param>
+    /// <param name="limit">Maximum number of history items to return. Default: 50.</param>
+    /// <param name="cancellationToken">Cancellation token for the HTTP request.</param>
+    /// <returns>History response with print jobs; empty list if request failed.</returns>
+    Task<MoonrakerHistoryResponse> GetPrintHistoryAsync(
+        string hostnameOrIp,
+        int port,
+        string? apiKey,
+        int limit = 50,
+        CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Fetches the current print statistics from the /printer/objects/query endpoint.
+    /// Returns real-time data including filament used, print duration,
+    /// and current print state for the active or most recent print.
+    /// </summary>
+    /// <param name="hostnameOrIp">The printer's hostname or IP address.</param>
+    /// <param name="port">The Moonraker API port (default: 7125).</param>
+    /// <param name="apiKey">Optional API key for authentication.</param>
+    /// <param name="cancellationToken">Cancellation token for the HTTP request.</param>
+    /// <returns>Print stats if successful; <c>null</c> if the request failed.</returns>
+    Task<MoonrakerPrintStats?> GetPrintStatsAsync(
+        string hostnameOrIp,
+        int port,
+        string? apiKey,
+        CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Fetches the current display status from the /printer/objects/query endpoint.
+    /// Returns progress percentage and status message for the active print.
+    /// Used by SignalR to push real-time progress updates to connected clients.
+    /// </summary>
+    /// <param name="hostnameOrIp">The printer's hostname or IP address.</param>
+    /// <param name="port">The Moonraker API port (default: 7125).</param>
+    /// <param name="apiKey">Optional API key for authentication.</param>
+    /// <param name="cancellationToken">Cancellation token for the HTTP request.</param>
+    /// <returns>Display status if successful; <c>null</c> if the request failed.</returns>
+    Task<MoonrakerDisplayStatus?> GetDisplayStatusAsync(
+        string hostnameOrIp,
+        int port,
+        string? apiKey,
+        CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Fetches the current filament usage data from the Moonraker server.
+    /// Returns a dictionary of usage metrics reported by the printer.
+    /// 
+    /// <para>
+    /// <b>Prefer GetPrintHistoryAsync or GetPrintStatsAsync for new code.</b>
+    /// This method is retained for backward compatibility with the
+    /// FilamentUsageSyncService and returns a dictionary of metric names
+    /// to their decimal values for callers that don't need typed DTOs.
+    /// </para>
+    /// </summary>
+    /// <param name="hostnameOrIp">The printer's hostname or IP address.</param>
+    /// <param name="port">The Moonraker API port (default: 7125).</param>
+    /// <param name="apiKey">Optional API key for authentication.</param>
+    /// <param name="cancellationToken">Cancellation token for the HTTP request.</param>
+    /// <returns>A dictionary of usage metric names to their decimal values.</returns>
+    Task<Dictionary<string, decimal>> GetFilamentUsageAsync(
+        string hostnameOrIp,
+        int port,
+        string? apiKey,
+        CancellationToken cancellationToken = default);
 }