feat(stats): count holidays connected to weekends (#68)

src/app/components/calendar-year/calendar-year.ts

@@ -202,6 +202,20 @@ export class CalendarYear {
 	}
 
 	protected readonly displayedPlan = this.userInput.displayedPlanSignal;
+	protected readonly weekendConnectedHolidays = computed(() => {
+		const isWeekend = (date: string) => {
+			const day = new Date(`${date}T00:00:00Z`).getUTCDay();
+			return day === 0 || day === 6;
+		};
+		// Weekday natural non-working dates are public holidays; declarations are separate.
+		return new Set(
+			(this.displayedPlan()?.timeOffPeriods ?? []).flatMap(({ nonWorkingDates }) =>
+				nonWorkingDates.some(isWeekend)
+					? nonWorkingDates.filter((date) => !isWeekend(date))
+					: [],
+			),
+		).size;
+	});
 	protected readonly earnedLeave = computed(() => {
 		const byRule = new Map<string, { ruleId: string; label: string; quantity: number }>();
 		for (const contribution of this.displayedPlan()?.ifThenContributions ?? []) {