Show the print-failure snapshot in the device error dialog

When a print fails, DeviceErrorDialog now fetches the printer's captured camera
frame of the failure and shows it in place of the generic HMS illustration,
falling back to the local image and a drawn placeholder on older plugins or errors.

- Agent: add get_hms_snapshot through NetworkAgent / IPrinterAgent (BBL calls the
  bound plugin symbol; other agents no-op, so old plugins degrade gracefully).
- DeviceManager: parse and clear m_print_error_img_id from the print-error message.
- Dialog: tiered cloud/local/placeholder image reusing the single image widget,
  with a liveness-guarded async callback decoded on the UI thread.

src/slic3r/GUI/DeviceManager.cpp

@@ -553,6 +553,7 @@ MachineObject::MachineObject(DeviceManager* manager, NetworkAgent* agent, std::s
     mc_print_sub_stage = 0;
     mc_left_time = 0;
     hw_switch_state = 0;
+    m_print_error_img_id = "";
 
     has_ipcam = true; // default true
 
@@ -3142,6 +3143,17 @@ int MachineObject::parse_json(std::string tunnel, std::string payload, bool key_
                         if (jj["print_error"].is_number())
                             print_error = jj["print_error"].get<int>();
                     }
+                    // Orca: keep the failure-snapshot id only while an error is active, so a stale
+                    // id can't leak into a later unrelated error dialog once the failure clears.
+                    if (print_error <= 0) {
+                        m_print_error_img_id.clear();
+                    }
+                    else if (jj.contains("err2") && jj["err2"].is_object()) {
+                        json err2 = jj["err2"];
+                        if (err2.contains("img_id") && err2["img_id"].is_string()) {
+                            m_print_error_img_id = err2["img_id"].get<std::string>();
+                        }
+                    }
 
                      DevStorage::ParseV1_0(jj, m_storage);