docs: reorganize localization guides

[gpbl]

Reorganize and clarify localization documentation so readers can find locale, time zone, translation, and calendar-specific guidance in dedicated sections with accurate examples and links.

Solution:

• Split localization content into focused pages (changing locale, time zones, ISO/broadcast week rules, Persian/Buddhist/Ethiopic/Hebrew calendars) and added a localization sidebar category.
• Moved translation guidance into the Guides area, restored formatter usage docs/anchors, and updated intra-site links plus Docusaurus redirects to the new paths.
• Refreshed examples to pull locales from DayPicker exports, clarified TZ usage with TZDate, and tuned copy for tone/clarity.