* Error return in `persistBlocks()` on initial `VmState` roblem
why:
previously threw an exception
* Updated sync mode option
why:
using enum rather than bool => space for more
* Added sync mode `full`, re-factued legacy sync
also:
rebased
* Fix typo (crashes `pesistBlocks()` otherwise)
also:
rebase to master
* Reduce log ticker noise by suppressing duplicate messages
* Clarify staged queue overflow handling
why:
backtrack/re-org mode in `stageItem()` should be detected by both,
the global indicator or the work item where it might have moved into.
also:
rebased