feat: enhance Mini App design guidelines and refactor layout components

- Updated Mini App design guidelines to include detailed instructions on UI changes, accessibility rules, and verification processes.
- Refactored multiple components to utilize `MiniAppScreen` and `MiniAppScreenContent` for consistent layout structure across the application.
- Improved error handling in `GlobalError` and `NotFound` components by integrating new layout components for better user experience.
- Introduced new hooks for admin functionality, streamlining access checks and data loading processes.
- Enhanced documentation to reflect changes in design policies and component usage, ensuring clarity for future development.

webapp-next/src/components/calendar/CalendarGrid.tsx

@@ -15,6 +15,7 @@ import type { CalendarEvent, DutyWithUser } from "@/types";
 import { dutiesByDate, calendarEventsByDate } from "@/lib/calendar-data";
 import { cn } from "@/lib/utils";
 import { CalendarDay } from "./CalendarDay";
+import { useTranslation } from "@/i18n/use-translation";
 
 export interface CalendarGridProps {
   /** Currently displayed month. */
@@ -37,6 +38,7 @@ export function CalendarGrid({
   onDayClick,
   className,
 }: CalendarGridProps) {
+  const { t } = useTranslation();
   const dutiesByDateMap = useMemo(
     () => dutiesByDate(duties),
     [duties]
@@ -67,7 +69,7 @@ export function CalendarGrid({
         className
       )}
       role="grid"
-      aria-label="Calendar"
+      aria-label={t("aria.calendar")}
     >
       {cells.map(({ date, key, month }, i) => {
         const isOtherMonth = month !== currentMonth.getMonth();