Add transaction-related events to the Database API

For inspiration see https://github.com/laravel/framework/tree/10.x/src/Illuminate/Database/E...

Reparenting.

On this

Started something, fit nicely with latest improvements in 📌 Refactor transactions Fixed . Looking forward to an early review - this sets the basis, more events are just more meat around this bone.

Postponed on 🐛 Strengthen TransactionManager Needs work

rebased

We cannot do this now, 🐛 Transaction autocommit during shutdown relies on unreliable object destruction order Active introduced Database::commitAllOnShutdown() which runs at a time when the event dispatcher has been destroyed already, so events fail. One more reason to move towards explicit commit.

eesh, seems not-ideal to wait until most-everything is destroyed to commit transactions, i.e. difficult to respond to various transaction commit failure modes.

As long as we can accept that these events are not dispatched when the event dispatcher service is not available - that is: 1) early in the request before the full container is available, and 2) during shutdown when the service can have already been destructed, this can proceed.

• 📌 [PP-1] Convert all transactions to explicit COMMIT Postponed would make this issue having some deprecated behaviour (i.e. including in the event information about the commit having occurred during destruct); however since that deprecation removal will be no sooner than D13 (2028?), I think it's worth keeping for now.
• 📌 Explore injecting the event dispatcher in the database service Active would make the event being dispatched also before full container availability - that could be a must-have if we want to move the post commit callback execution to an event-based solution.

Still needs some tests for commit/release/rollback failure events - not easy to create the context - so I will look into mocking.

But the biggest part here is already reviewable.

Working on the unit tests.

I think we need to add an additional event for the autocommit on DDL, separate from the regular one, and still emit the regular one in the expected moment even if the autocommit already happened. This will make simpler moving post-transaction callbacks to event subscriptions.

AFK for a while, will come back later.