feat(ui): add persistent bilingual settings and combat HUD

Tools/Unity/WindowsReadme.txt

@@ -8,6 +8,11 @@ UnityPlayer.dll、MonoBleedingEdge 和 ThirdPartyNotices。
 重启后保留。可用鼠标选择；列表内 Tab / Shift+Tab 切换选项，
 Enter / Space 确认，Esc 或点击外部收起。
 
+主页和暂停菜单均可进入「设置」，调整总音量、画质、分辨率、
+窗口 / 全屏、鼠标灵敏度与精瞄倍率，并修改键鼠绑定。
+点击「应用并保存」后保存；显示变化需在 15 秒内确认，否则自动恢复。
+返回会放弃未应用的修改，恢复默认也需应用后保存。以下为默认键位。
+
 WASD 移动，鼠标瞄准；左键主武器，右键精瞄。
 V 切换越肩 / 第一人称，Shift 推进，Space 跳跃 / 轻型升空。
 Q 副武装，F 主动防护，E 交互，Tab 货仓，Esc 暂停。
@@ -20,6 +25,12 @@ The bottom-right Language button switches Simplified Chinese and English instant
 Your language choice is remembered across restarts. Tab / Shift+Tab navigates
 the language list, Enter / Space confirms, and Esc or an outside click closes it.
 
+Open Settings from the home or pause menu for volume, graphics quality,
+resolution, window mode, mouse/aim sensitivity and key bindings.
+Select Apply and save to persist changes. Confirm display changes within
+15 seconds or the previous display settings return. Back discards pending edits.
+Restoring defaults also requires Apply. The controls below are the defaults.
+
 WASD: move; mouse: aim; LMB/RMB: fire/precision aim; V: perspective;
 Shift: boost; Space: jump/lift; Q: secondary; F: shield; E: interact;
 Tab: cargo; hold G while standing still: send selected cargo; Esc: pause.