Fix JSON format helpers, update HAL and LCD driver

Fix snprintf usage and UTC offset formatting in json_format_helpers.h to avoid buffer-size issues and correct sign handling. Update lib-hal/include/gd32/hal.h: bump copyright years, add IWYU pragmas for retained includes, and simplify ENABLE_USB_HOST conditional + unify usbh_host usage; preserve softwaretimers/hwclock includes. Refactor lib-rdmsubdevice/src/spi/rdmsubdevicebwlcd.cpp: bump copyright year, modernize naming and formatting, introduce constants for DMX footprint and default line, replace TO_HEX macro with common hex utility, clean up Data/Display/Update logic and formatting, and improve overall readability without changing intended functionality.

Author: vanvught

common/include/json/json_format_helpers.h

@@ -36,23 +36,22 @@ constexpr size_t kOffsetBufferSize = 12; // For timezone offsets e.g. "+01:00"
 
 [[nodiscard]] inline const char* FormatFloat(float value, char (&buf)[kFloatBufferSize], const char* fmt = "%.2f")
 {
-    snprintf(buf, sizeof(buf) - 1, fmt, value);
+    snprintf(buf, sizeof(buf), fmt, value);
     return buf;
 }
 
 [[nodiscard]] inline const char* FormatUtcOffset(int32_t hours, uint32_t minutes, char (&buf)[kOffsetBufferSize])
 {
-    if (hours == 0)
+    if (hours <= 0)
     {
-        snprintf(buf, sizeof(buf) - 1, "%.2d:%.2u", hours, minutes);
+        snprintf(buf, sizeof(buf), "%.2d:%.2u", hours, minutes);
     }
     else
     {
-        snprintf(buf, sizeof(buf) - 1, "%c%.2d:%.2u", hours < 0 ? '-' : '+', hours, minutes);
+        snprintf(buf, sizeof(buf), "+%.2d:%.2u", hours, minutes);
     }
     return buf;
 }
-
 } // namespace format
 
 #endif  // JSON_JSON_FORMAT_HELPERS_H_

lib-hal/include/gd32/hal.h

@@ -2,7 +2,7 @@
  * @file hal.h
  *
  */
-/* Copyright (C) 2025 by Arjan van Vught mailto:info@gd32-dmx.org
+/* Copyright (C) 2025-2026 by Arjan van Vught mailto:info@gd32-dmx.org
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -28,17 +28,13 @@
 
 #include <cstdint>
 
-#include "gd32.h"
+#include "gd32.h" // IWYU pragma: keep
 
-#if defined(ENABLE_USB_HOST) && defined(CONFIG_USB_HOST_MSC)
+#if defined(ENABLE_USB_HOST)
 extern "C"
 {
 #include "usbh_core.h"
-#if defined(GD32H7XX) || defined(GD32F4XX)
-    extern usbh_host usb_host_msc;
-#else
     extern usbh_host usb_host;
-#endif
 }
 #endif
 
@@ -54,10 +50,10 @@ void emac_debug_run();
 #include "task.h"
 #endif
 
-#include "softwaretimers.h"
+#include "softwaretimers.h" // IWYU pragma: keep
 
 #if !defined(DISABLE_RTC)
-#include "hwclock.h"
+#include "hwclock.h" // IWYU pragma: keep
 #endif
 
 #include "hal_panelled.h"
@@ -74,13 +70,9 @@ inline constexpr float kCoreTemperatureMax = +85.0;
 
 inline void Run()
 {
-#if defined(ENABLE_USB_HOST) && defined(CONFIG_USB_HOST_MSC)
-#if defined(GD32H7XX) || defined(GD32F4XX)
-    usbh_core_task(&usb_host_msc);
-#else
+#if defined(ENABLE_USB_HOST)
     usbh_core_task(&usb_host);
 #endif
-#endif
 #if !defined(USE_FREE_RTOS)
     SoftwareTimerRun();
 #endif