Centralize time calculation and recovery

AdvancedCore/src/main/java/com/bencodez/advancedcore/api/time/TimeCalculation.java

@@ -0,0 +1,31 @@
+package com.bencodez.advancedcore.api.time;
+
+import java.time.Clock;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+import java.time.temporal.WeekFields;
+import java.util.Locale;
+
+/**
+ * Shared deterministic time calculations used by Bukkit and proxy time checkers.
+ */
+public final class TimeCalculation {
+
+	private TimeCalculation() {
+	}
+
+	public static LocalDateTime currentTime(Clock clock, String timeZone, int hourOffset) {
+		Clock effectiveClock = clock == null ? Clock.systemDefaultZone() : clock;
+		ZonedDateTime now = ZonedDateTime.now(effectiveClock);
+		if (timeZone != null && !timeZone.isEmpty()) {
+			now = now.withZoneSameInstant(ZoneId.of(timeZone));
+		}
+		return now.toLocalDateTime().plusHours(hourOffset);
+	}
+
+	public static int weekNumber(LocalDateTime time, int weekOffset, Locale locale) {
+		Locale effectiveLocale = locale == null ? Locale.getDefault() : locale;
+		return time.plusDays(weekOffset).get(WeekFields.of(effectiveLocale).weekOfWeekBasedYear());
+	}
+}