feat: Enhance session handling in timetable and UI

- Introduced session types (exams, credits, consultations, coursework defenses) with distinct icons and colors for better visibility in the UI.
- Updated PlansScreen, ScheduleScreen, and WeekGrid to display session information appropriately.
- Modified CalendarView and PlansView to include session indicators in the calendar and plans.
- Enhanced LessonCard and CompactLesson to show session details and adjust styling based on session presence.
- Added new SessionMark component for consistent session representation across Android and iOS.
- Updated server logic to handle session entries from external documents, ensuring accurate timetable representation.
- Improved date parsing to accommodate session-related dates in various formats.
- Added tests to verify session handling and date parsing functionality.

shared/weeks.d.ts

@@ -53,6 +53,7 @@ interface WeekLesson {
 }
 export function parseWeekRanges(condition: string): WeekRange[] | null;
 export function parseTextDates(raw: string, year: string | number): string[];
+export const DATE_LIST: RegExp;
 export function isoDate(time: number): string;
 export function addDays(iso: string, days: number): string;
 export function weekday(iso: string): number;