- Fix _isoWeek: correct Sunday shift (-3 instead of +4), use floor+1 formula,
match jan1 timezone to input — planned meals now appear correctly for UTC+ users
- Add kPlanningHorizonDays=28 / kMenuPastWeeks=8 constants; apply to home date
strip, plan picker (strip + calendar), and menu screen prev/next navigation
- Menu screen week nav: disable arrows at min/max limits using compareTo
- Home screen: replace _GenerateActionCard/_WeekPlannedChip conditional with
always-visible _FutureDayPlanButton(dateString); show _DayPlannedChip only
when the specific day has planned meals; remove standalone _PlanMenuButton
- _FutureDayPlanButton uses selected date as defaultStart instead of lastPlanned+1
- Rename weekPlannedLabel -> dayPlannedLabel across all 12 locales
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>