Version 6 only adds the driving settings store; dropping the area cache
is version 7. The case name claimed both, so it now names only the new
store and a comment explains where the empty area cache it still checks
comes from.
Each version() of the offline database runs once, on a user's device, when a
new bundle opens what an older one wrote. None of them ran in CI: the v3 blob
cache backfill and the v8 area-fingerprint reset had never been exercised
against an older database.
The new test builds the database as each previous version left it in
fake-indexeddb, seeds a row into every table it had, opens it with the current
schema and checks that the rows survived and that the version did what it is
for. A guard reads the declared versions from offlineDb.ts and fails on a
duplicate, on a version without an upgrade case, or on stores the history
fixture does not reproduce. TrekOfflineDb is exported so the test can open a
named database with it.
Maurice