feature: hud (#37)

* build: replace FetchContent with direct includes for glm

* build(deps): replace SOIL2 with stb for image and vorbis decoding

* build: replace FetchContent with direct includes for toml++

* refactor(texture): bump block texture size to 512 and disable items tab

* feat: add hotbar system with ItemStack and RowLayout

* fix(ui): restrict Ctrl key handling to typing mode

* feat(ui): add widget border support and highlight selected hotbar slot

* fix(ui): update borders on scale change and correct Image width

- Added update_border() calls in set_scale() for Button, ChatBox, Image, Label, and TextField.
- Fixed Image::width() to multiply by width instead of height.
- Added early return in Widget::update_border() if border is not supported.

* feat(ui): add border visual feedback on slider drag

* feat(ui): add ItemSlot widget and refactor hotbar to use it

* feat(world_scene): add inventory UI and pause type enum

* feat(ui): add item slot tooltip and make window size static

* fix(ui label): account for background offset in width/height

* refactor(ui): centralize item info label in inventory and add update

* feat(ui): add hotbar interaction in inventory UI

* fix(inventory-ui): correct row creation logic for first item

The loop starting at index 0 created a new row on the first iteration
(i % 10 == 0). Shift the loop to start at 1 and adjust modulus condition
to create rows correctly every 10 items.

* feat(block): add name_key for localized block names

Add `name_key` field to all block TOML definitions, enabling per-block localization. Update `BlockData` struct and `BlockManager` with `local_name()` method that returns a localized string via the translation system. Add corresponding entries to `en_US.json` and `zh_CN.json`. Modify inventory UI to use the localized name when displaying block info, and fix a bug where emptying a hotbar slot did not clear the item locally.

* fix(ui): change inventory item slot color from white to gray

* fix(ui): add missing include for std::array

include/glm/gtx/mixed_product.hpp

@@ -0,0 +1,39 @@
+/// @ref gtx_mixed_product
+/// @file glm/gtx/mixed_product.hpp
+///
+/// @see core (dependence)
+///
+/// @defgroup gtx_mixed_product GLM_GTX_mixed_producte
+/// @ingroup gtx
+///
+/// Include <glm/gtx/mixed_product.hpp> to use the features of this extension.
+///
+/// Mixed product of 3 vectors.
+
+#pragma once
+
+// Dependency:
+#include "../glm.hpp"
+
+#ifndef GLM_ENABLE_EXPERIMENTAL
+#	error "GLM: GLM_GTX_mixed_product is an experimental extension and may change in the future. Use #define GLM_ENABLE_EXPERIMENTAL before including it, if you really want to use it."
+#elif GLM_MESSAGES == GLM_ENABLE && !defined(GLM_EXT_INCLUDED)
+#	pragma message("GLM: GLM_GTX_mixed_product extension included")
+#endif
+
+namespace glm
+{
+	/// @addtogroup gtx_mixed_product
+	/// @{
+
+	/// @brief Mixed product of 3 vectors (from GLM_GTX_mixed_product extension)
+	template<typename T, qualifier Q>
+	GLM_FUNC_DECL T mixedProduct(
+		vec<3, T, Q> const& v1,
+		vec<3, T, Q> const& v2,
+		vec<3, T, Q> const& v3);
+
+	/// @}
+}// namespace glm
+
+#include "mixed_product.inl"