Fix recurrent event splitting being broken after prior refactoring.

src/stores/CalendarStore.js

@@ -289,7 +289,7 @@ export const useCalendarStore = defineStore('calendar', {
       this.notifyEventsChanged()
     },
 
-    splitMoveVirtualOccurrence(baseId, occurrenceDateStr, newStartStr, newEndStr) {
+    splitMoveVirtualOccurrence(baseId, occurrenceDateStr, newStartStr, newEndStr, occurrenceIndex) {
       const base = this.events.get(baseId)
       if (!base || !base.recur) return
       const originalCountRaw = base.recur.count
@@ -310,7 +310,8 @@ export const useCalendarStore = defineStore('calendar', {
         this.setEventRange(baseId, newStartStr, newEndStr, { mode: 'move', rotatePattern: true })
         return baseId
       }
-      if (occurrenceDate <= baseStart) {
+      // Use occurrenceIndex when provided to detect first occurrence (n == 0)
+      if (occurrenceIndex === 0 || occurrenceDate.getTime() === baseStart.getTime()) {
         this.setEventRange(baseId, newStartStr, newEndStr, { mode: 'move' })
         return baseId
       }