fix: use in-memory startedAt for cron job log to survive DB restore

The auto-import wipes the database, destroying the cronJobLog record
created at the start of the job. Now duration is calculated from a
local variable instead of querying the DB, and if the record is gone
a fresh log entry is created in the restored database.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/db/generated/prisma/schema.prisma

@@ -23,7 +23,9 @@ model User {
   username             String                @unique
   password             String
   autoBackupEnabled    Boolean               @default(true)
+  autoBackupHour       Int                   @default(20)
   usbBackupEnabled     Boolean               @default(false)
+  usbBackupHour        Int                   @default(21)
   patients             Patient[]
   appointments         Appointment[]
   staff                Staff[]