transaction: no longer explicitly cache bookmarks The transaction file generation is already dealing with the backup for this. So, no need to duplicate such backup.

transaction: no longer explicitly cache phaseroots The transaction file generation is already dealing with the backup for this. So, no need to duplicate such backup.

narrow: enforce that narrow spec is written within a transaction

narrow: write the narrow spec in a transaction during share It will be simpler if all write happens within transaction.

narrow: open the transaction sooner when unbundling That way, the narrow spec changes will be done within a transaction.

narrow: write the narrow spec in a transaction during clone It will be simpler if all write happens within transaction.

narrow: drop the dedicated backup code Now that the transaction manage the writes, we can simply use the transaction for backup. Some extra cleanup to ensure all changes happens within a transaction will be made in the next changesets.