Basic logging: log entity create/update/delete events

[strobelm]

Maybe sth. less controversial as first larger PR. My PHP is a bit rusty (pun intended) :), a review would be very helpful.

This PR replaces the unused Log stub with a new schema (auto-id, user FK, username snapshot, datetime, entity class+id, JSON changes, IP).

A Doctrine listener collects changesets in onFlush and writes Log rows via the background EM in postFlush, same as LastActionSubscriber. Updates store only changed fields; creates and deletes store full snapshots.

Password, salt, token, secret, apiKey and privateKey fields are stored as redacted. Log, WorkflowLog, MonthlyStatsSnapshot and User.lastAction are filtered out.

Produces logs like this

id	user_id	username	date	entity_class	entity_id	action	changes	ip_address
9	1	admin	2026-05-13 08:45:50	App\Entity\InvoiceAppartment	3	delete	{"id":[3,null],"number":["7",null],"description":["Doppelzimmer mit Dachfenster",null],"beds":[2,null],"persons":[2,null],"startDate":["2026-05-12T00:00:00+00:00",null],"endDate":["2026-05-13T00:00:00+00:00",null],"price":["42.00",null],"vat":[7.0,null],"includesVat":[true,null],"isFlatPrice":[false,null],"isPerRoom":[false,null]}	172.23.0.1

Closes #19.

[developeregrem]

Hi @strobelm thanks a lot! Looks quit good at the moment. I will test it in the next few days.
One thing we should keep in mind is log retention. Especially the IP adress is a PII which needs to be handles carefully (GDPR). Therefore, I would suggest maybe a command which deletes old log entries based on a configurable period. This command can be triggered e.g. via cron job.

[strobelm]

@developeregrem thanks for the feedback.

Good point on the the logging of IP addresses. I re-used the existing workflow purge mechanism and unified it in a app:purge-logs command. Hope this works for you.