🎉 feat(i18n): integrate Semi UI LocaleProvider with dynamic i18next language support

Add Semi UI internationalization to the project by wrapping the root
component tree with `LocaleProvider`. A new `SemiLocaleWrapper`
component maps the current `i18next` language code to the corresponding
Semi locale (currently `zh_CN` and `en_GB`) and falls back to Chinese
when no match is found.

Key changes
-----------
1. web/src/index.js
   • Import `LocaleProvider`, `useTranslation`, and Semi locale files.
   • Introduce `SemiLocaleWrapper` to determine `semiLocale` from
     `i18next.language` using a concise prefix-based mapping.
   • Wrap `PageLayout` with `SemiLocaleWrapper` inside the existing
     `ThemeProvider`.

2. Ensures that all Semi components automatically display the correct
   language when the app language is switched via i18next.

BREAKING CHANGE
---------------
Applications embedding this project must now ensure that `i18next`
initialization occurs before React render so that `LocaleProvider`
receives the correct initial language.

web/src/i18n/locales/en.json

@@ -1189,7 +1189,6 @@
   "令牌无法精确控制使用额度，只允许自用，请勿直接将令牌分发给他人。": "Tokens cannot accurately control usage, only for self-use, please do not distribute tokens directly to others.",
   "添加兑换码": "Add redemption code",
   "复制所选兑换码到剪贴板": "Copy selected redemption codes to clipboard",
-  "第 {{start}} - {{end}} 条，共 {{total}} 条": "Items {{start}} - {{end}} of {{total}}",
   "新建兑换码": "Code",
   "兑换码更新成功！": "Redemption code updated successfully!",
   "兑换码创建成功！": "Redemption code created successfully!",