DatePicker: localise the hardcoded "Today" label in CalendarHeader

[millus]

The TodayPicker button in CalendarHeader.tsx renders a hardcoded English string while everything else goes through I18nProvider. Pre-existing issue, not introduced by any recent PR. Good candidate to address when building the EDS 2.0 (/next) version of DatePicker.

[claude]

Thanks for filing this! A few existing issues look related and may be worth a look before picking this up:

• EDS DatePicker shows warning in the wrong language #4252 — EDS DatePicker shows warning in the wrong language (closed as completed): same root pattern in the same component — a DatePicker string that ignored the surrounding I18nProvider. The fix there moved I18nProvider above the react-aria hooks rather than around the returned JSX, so the resolution may be a useful reference (or may already cover part of the plumbing needed here).
• Pagination: allow localizing/overriding the hardcoded English ARIA labels #5100 — Pagination: allow localizing/overriding the hardcoded English ARIA labels (open): the same class of defect in another eds-core-react component — hardcoded English strings with no public API to override or localise them. Worth aligning on a single approach for both.
• 🐛 Datepicker Input | Today button does not work correctly #4933 — 🐛 Datepicker Input | Today button does not work correctly (open): a behavioural bug on the exact same TodayPicker button in CalendarHeader.tsx, so the two could reasonably be addressed together.

This comment was generated by an LLM and may be inaccurate. Please verify that the linked issues are actually relevant.