- GetQueueAttributes now returns FifoQueue, ContentBasedDeduplication, Policy and
real Created/LastModifiedTimestamp (previously missing/stubbed '0000000000')
- Queue: add CreatedAt, LastModifiedAt, Policy, ContentBasedDeduplication
- parse FifoQueue/ContentBasedDeduplication in both protocols (StringToBool)
- Policy/RedriveAllowPolicy: normalize JSON-string form to object (JSON protocol
sent them as string -> SetQueueAttributes failed with InvalidParameterValue)
- persistence: keep new fields in meta DTO + backfill empty timestamps on load
- FIFO dedup is inherent: IsDuplicate/InitDuplicatation gate on IsFIFO only
(env flag EnableDuplicates=false disabled dedup for all FIFO queues)