feat(calendar): add explained period feature and update translations

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

@@ -68,6 +68,9 @@ export class CalendarMonth implements OnInit {
 	@Input()
 	currentDate: string | null = null;
 
+	@Input()
+	explainedPeriod?: { start: string; end: string };
+
 	@Input()
 	dateStatuses: Readonly<Record<string, CalendarDayStatus>> = {};
 
@@ -94,6 +97,15 @@ export class CalendarMonth implements OnInit {
 		return this.dateStatuses[this.getDateKey(day)];
 	}
 
+	isInExplainedPeriod(day: Date): boolean {
+		const date = this.getDateKey(day);
+		return (
+			!!this.explainedPeriod &&
+			date >= this.explainedPeriod.start &&
+			date <= this.explainedPeriod.end
+		);
+	}
+
 	getStatusMarker(day: Date): string {
 		switch (this.getStatus(day)?.change) {
 			case 'added':
@@ -145,6 +157,10 @@ export class CalendarMonth implements OnInit {
 		}
 		const parts = [this.dayFormatter.format(day)];
 		if (tooltip) parts.push(tooltip);
+		if (this.getDateKey(day) === this.currentDate)
+			parts.push(this.translationService.tr().planning.currentPlacement);
+		if (this.isInExplainedPeriod(day))
+			parts.push(this.translationService.tr().planning.explainedPeriod);
 		if (!this.isInHorizon(day))
 			parts.push(this.translationService.tr().planning.outsideHorizon);
 		return parts.join('. ');