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

assets/lang/en_US.json

@@ -35,5 +35,15 @@
     "joingame.join_a_world": "Join A World",
     "joingame.server_ip": "Server Ip",
     "joingame.join_world": "Join World",
-    "error.disable_voice": "Server Disable Voice Chat"
+    "error.disable_voice": "Server Disable Voice Chat",
+    "block.air": "air",
+    "block.dirt": "dirt",
+    "block.grass_block": "grass block",
+    "block.grass": "grass",
+    "block.leaf": "leaf",
+    "block.log": "log",
+    "block.sand": "sand",
+    "block.snowy_grass_block": "snowy grass block",
+    "block.stone": "stone",
+    "block.water": "water"
 }

assets/lang/zh_CN.json

@@ -35,5 +35,15 @@
     "joingame.join_a_world": "加入世界",
     "joingame.server_ip": "服务器IP",
     "joingame.join_world": "加入世界",
-    "error.disable_voice": "服务器已禁用语音聊天"
+    "error.disable_voice": "服务器已禁用语音聊天",
+    "block.air": "空气",
+    "block.dirt": "泥土",
+    "block.grass_block": "草方块",
+    "block.grass": "草",
+    "block.leaf": "树叶",
+    "block.log": "原木",
+    "block.sand": "沙子",
+    "block.snowy_grass_block": "覆雪草方块",
+    "block.stone": "石头",
+    "block.water": "水"
 }