🎉 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/components/table/TokensTable.js

@@ -893,12 +893,6 @@ const TokensTable = () => {
             total: tokenCount,
             showSizeChanger: true,
             pageSizeOptions: [10, 20, 50, 100],
-            formatPageText: (page) =>
-              t('第 {{start}} - {{end}} 条，共 {{total}} 条', {
-                start: page.currentStart,
-                end: page.currentEnd,
-                total: tokenCount,
-              }),
             onPageSizeChange: handlePageSizeChange,
             onPageChange: handlePageChange,
           }}