- Add i18n support to admin sidebar, breadcrumbs, and nav-footer
- Add i18n support to admin pages: system-settings, users, versions, risk-control, sessions, cloud-variables, cloud-constants
- Add i18n support to auth pages: login, register
- Add i18n support to install and profile pages
- Add i18n support to agent pages: dashboard, finance, users, apps, cards
- Replace all hard-coded Chinese text with i18n translation keys
- Add comprehensive translation keys to zh.json and en.json
- Fix date formatting to use locale-agnostic toLocaleDateString()
- Pass t function as parameter for i18n in non-component files