refactor(gui): reorganize background rendering and layout helpers

- Moved background rendering functionality from the editor to a dedicated GUI module, enhancing modularity and separation of concerns.
- Introduced layout helpers for consistent theme-aware sizing across the GUI, improving UI consistency and maintainability.
- Updated CMake configuration to reflect the new structure, ensuring proper linkage of the background renderer and layout helpers.

Benefits:
- Improved organization of GUI components, facilitating easier updates and enhancements.
- Enhanced user interface consistency through theme-aware layout management.

src/util/hyrule_magic.cc

@@ -0,0 +1,72 @@
+#include "util/hyrule_magic.h"
+
+namespace yaze {
+namespace zelda3 {
+
+namespace {
+
+// "load little endian value at the given byte offset and shift to get its
+// value relative to the base offset (powers of 256, essentially)"
+unsigned ldle(uint8_t const *const p_arr, unsigned const p_index) {
+  uint32_t v = p_arr[p_index];
+  v <<= (8 * p_index);
+  return v;
+}
+
+void stle(uint8_t *const p_arr, size_t const p_index, unsigned const p_val) {
+  uint8_t v = (p_val >> (8 * p_index)) & 0xff;
+  p_arr[p_index] = v;
+}
+
+void stle0(uint8_t *const p_arr, unsigned const p_val) {
+  stle(p_arr, 0, p_val);
+}
+
+void stle1(uint8_t *const p_arr, unsigned const p_val) {
+  stle(p_arr, 1, p_val);
+}
+
+void stle2(uint8_t *const p_arr, unsigned const p_val) {
+  stle(p_arr, 2, p_val);
+}
+
+void stle3(uint8_t *const p_arr, unsigned const p_val) {
+  stle(p_arr, 3, p_val);
+}
+
+// Helper function to get the first byte in a little endian number
+uint32_t ldle0(uint8_t const *const p_arr) { return ldle(p_arr, 0); }
+
+// Helper function to get the second byte in a little endian number
+uint32_t ldle1(uint8_t const *const p_arr) { return ldle(p_arr, 1); }
+
+// Helper function to get the third byte in a little endian number
+uint32_t ldle2(uint8_t const *const p_arr) { return ldle(p_arr, 2); }
+
+// Helper function to get the third byte in a little endian number
+uint32_t ldle3(uint8_t const *const p_arr) { return ldle(p_arr, 3); }
+
+}  // namespace
+
+void stle16b_i(uint8_t *const p_arr, size_t const p_index,
+               uint16_t const p_val) {
+  stle16b(p_arr + (p_index * 2), p_val);
+}
+
+void stle16b(uint8_t *const p_arr, uint16_t const p_val) {
+  stle0(p_arr, p_val);
+  stle1(p_arr, p_val);
+}
+
+uint16_t ldle16b(uint8_t const *const p_arr) {
+  uint16_t v = 0;
+  v |= (ldle0(p_arr) | ldle1(p_arr));
+  return v;
+}
+
+uint16_t ldle16b_i(uint8_t const *const p_arr, size_t const p_index) {
+  return ldle16b(p_arr + (2 * p_index));
+}
+
+}  // namespace zelda3
+}  // namespace yaze

src/util/hyrule_magic.h

@@ -0,0 +1,31 @@
+#ifndef YAZE_UTIL_HYRULE_MAGIC_H
+#define YAZE_UTIL_HYRULE_MAGIC_H
+
+#include <cstdint>
+#include <cstring>
+
+namespace yaze {
+namespace zelda3 {
+/**
+ * @brief Store little endian 16-bit value using a byte pointer, offset by an
+ * index before dereferencing
+ */
+void stle16b_i(uint8_t *const p_arr, size_t const p_index,
+               uint16_t const p_val);
+
+void stle16b(uint8_t *const p_arr, uint16_t const p_val);
+
+/**
+ * @brief Load little endian halfword (16-bit) dereferenced from an arrays of
+ * bytes. This version provides an index that will be multiplied by 2 and added
+ * to the base address.
+ */
+uint16_t ldle16b_i(uint8_t const *const p_arr, size_t const p_index);
+
+// Load little endian halfword (16-bit) dereferenced from
+uint16_t ldle16b(uint8_t const *const p_arr);
+
+}  // namespace zelda3
+}  // namespace yaze
+
+#endif  // YAZE_UTIL_HYRULE_MAGIC_H

src/util/util.cmake

@@ -17,7 +17,7 @@ set(YAZE_UTIL_SRC
   util/log.cc
   util/platform_paths.cc
   util/file_util.cc
-  util/platform_paths.cc
+  util/hyrule_magic.cc  # Byte order utilities (moved from zelda3)
 )
 
 add_library(yaze_util STATIC ${YAZE_UTIL_SRC})