[PP-1] Convert all transactions to explicit COMMIT

mondrake → changed the visibility of the branch 3406985-pp-1-convert-all to hidden.

mondrake → changed the visibility of the branch 3406985-pp-1-convert-all to active.

mondrake → changed the visibility of the branch 3406985-pp-1-convert-all to hidden.

mondrake → changed the visibility of the branch 3406985-pp-1-convert-all to active.

mondrake → changed the visibility of the branch 3406985-pp-1-convert-all to hidden.

mondrake → changed the visibility of the branch 3406985-pp-1-convert-all to active.

It would be helpful to have a small summary on the why in the issue summary

Blocker is in, tagging per #12.

Updated IS.

Some point were raised in Slack https://drupal.slack.com/archives/C1BMUQ9U6/p1747310837078309

made suggested changes, thanks @alexpott

Added specific deprecation tests for the implicit commit behavior and for ::commitAll() when there are pending transactions open.