Exercises the lifecycleAbortMPU handler path that the prefix-based
expiration tests can't reach — routing keys off of .uploads/<id>/
directory events, not regular object events, and the dispatcher uses
a different RPC path (rm on the .uploads/<id>/ folder).
Setup: AbortIncompleteMultipartUpload rule with DaysAfterInitiation=1,
CreateMultipartUpload, UploadPart (so the directory carries the
right shape), backdate the .uploads/<uploadID>/ directory entry 30
days, run the worker. The upload must drop out of
ListMultipartUploads.
Helpers added: putAbortMPULifecycle, backdateUploadDir.