Show the batching choice for the current synchronisation mode while
preserving both mode preferences. Observe local save failures before
file-open work and report failed asynchronous unload preparation.
Record the accepted recovery and batching contract, update the primary
settings documentation, and add two-device runtime coverage for batching,
deletions, saved settings, and interrupted local processing.
Requires Commonlib commit 72bdc66af5d7338d8f2f69ebe83c3866def93360.
Update the exact registry dependency when its package version is published.
Validation: full repository check; latest packed dependency type checks,
production build, 1,373 unit tests (one skipped), and six focused runtime
recovery cases. The earlier implementation passed the full 23-case runtime
comparison and five additional interruption conditions.