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/fast_square_root.inl

@@ -0,0 +1,75 @@
+/// @ref gtx_fast_square_root
+
+namespace glm
+{
+	// fastSqrt
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType fastSqrt(genType x)
+	{
+		GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559 || GLM_CONFIG_UNRESTRICTED_FLOAT, "'fastSqrt' only accept floating-point input");
+
+		return genType(1) / fastInverseSqrt(x);
+	}
+
+	template<length_t L, typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER vec<L, T, Q> fastSqrt(vec<L, T, Q> const& x)
+	{
+		return detail::functor1<vec, L, T, T, Q>::call(fastSqrt, x);
+	}
+
+	// fastInversesqrt
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType fastInverseSqrt(genType x)
+	{
+		return detail::compute_inversesqrt<1, genType, lowp, detail::is_aligned<lowp>::value>::call(vec<1, genType, lowp>(x)).x;
+	}
+
+	template<length_t L, typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER vec<L, T, Q> fastInverseSqrt(vec<L, T, Q> const& x)
+	{
+		return detail::compute_inversesqrt<L, T, Q, detail::is_aligned<Q>::value>::call(x);
+	}
+
+	// fastLength
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType fastLength(genType x)
+	{
+		GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559 || GLM_CONFIG_UNRESTRICTED_FLOAT, "'fastLength' only accept floating-point inputs");
+
+		return abs(x);
+	}
+
+	template<length_t L, typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER T fastLength(vec<L, T, Q> const& x)
+	{
+		GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559 || GLM_CONFIG_UNRESTRICTED_FLOAT, "'fastLength' only accept floating-point inputs");
+
+		return fastSqrt(dot(x, x));
+	}
+
+	// fastDistance
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType fastDistance(genType x, genType y)
+	{
+		return fastLength(y - x);
+	}
+
+	template<length_t L, typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER T fastDistance(vec<L, T, Q> const& x, vec<L, T, Q> const& y)
+	{
+		return fastLength(y - x);
+	}
+
+	// fastNormalize
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType fastNormalize(genType x)
+	{
+		return x > genType(0) ? genType(1) : -genType(1);
+	}
+
+	template<length_t L, typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER vec<L, T, Q> fastNormalize(vec<L, T, Q> const& x)
+	{
+		return x * fastInverseSqrt(dot(x, x));
+	}
+}//namespace glm