Merge branch 'jt/receive-pack-use-odb-transactions'

'git receive-pack' has been refactored to use ODB transaction interfaces instead of directly managing 'tmp_objdir' for staging incoming objects, bringing it closer to being ODB backend agnostic. * jt/receive-pack-use-odb-transactions: builtin/receive-pack: stage incoming objects via ODB transactions builtin/receive-pack: drop redundant tmpdir env odb/transaction: introduce ODB transaction flags odb/transaction: add transaction env interface odb/transaction: propagate commit errors odb/transaction: propagate begin errors object-file: propagate files transaction errors object-file: drop check for inflight transactions object-file: embed transaction flush logic in commit function object-file: rename files transaction fsync function object-file: rename files transaction prepare function