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/ext/matrix_float3x2.hpp

@@ -0,0 +1,18 @@
+/// @ref core
+/// @file glm/ext/matrix_float3x2.hpp
+
+#pragma once
+#include "../detail/type_mat3x2.hpp"
+
+namespace glm
+{
+	/// @addtogroup core_matrix
+	/// @{
+
+	/// 3 columns of 2 components matrix of single-precision floating-point numbers.
+	///
+	/// @see <a href="http://www.opengl.org/registry/doc/GLSLangSpec.4.20.8.pdf">GLSL 4.20.8 specification, section 4.1.6 Matrices</a>
+	typedef mat<3, 2, float, defaultp>			mat3x2;
+
+	/// @}
+}//namespace glm