syncAll() ran each enabled type's sync in sequence with no per-type
error handling, so one type throwing (e.g. its vault folder missing)
aborted the whole run and skipped libraryLastSync -- every other
enabled type silently never synced. Each type's runSync is now wrapped
individually: failures are logged (and surfaced via Notice unless
quiet) and the loop continues; libraryLastSync still updates after the
loop regardless.
Also: dry-run sync previews now route spec-level flip notifications
(the "chapter/issue out" Notices) through the log instead of a real
Notice, since a dry run never actually writes the change it's
describing.
