1. add global i18n fallback toast on lang:fallback event, only show once per process
2. add getCachedBundleAny to retrieve expired cache for boot fallback
3. add cache fallback logic when remote i18n bundle load fails
1. add cache for privacy check result to reduce repeated calls
2. refactor lang bundle boot process with integrity checks
3. add timeout recovery for late fetch responses
4. improve error handling and fallback logic
5. add comments for better maintainability
