clarify completedTimeTo is exclusive in Javadoc

Author: bachuv

exporthistory/src/main/java/com/microsoft/durabletask/exporthistory/models/ExportJobCreationOptions.java

@@ -55,7 +55,8 @@ public ExportJobCreationOptions() {
      * @param jobId               the job ID, or {@code null} to auto-generate
      * @param mode                the export mode (BATCH or CONTINUOUS)
      * @param completedTimeFrom   inclusive start of the completed time window
-     * @param completedTimeTo     inclusive end of the completed time window (required for BATCH, null for CONTINUOUS)
+     * @param completedTimeTo     exclusive end of the completed time window — must be strictly after
+     *                            {@code completedTimeFrom} (required for BATCH, null for CONTINUOUS)
      * @param destination         blob storage destination, or {@code null} to use defaults
      * @param format              export format, or {@code null} for default (JSONL+gzip)
      * @param runtimeStatus       runtime status filter, or {@code null} for all terminal statuses