[Bug]: FileSystem update and post_update signals do not dispatch events with IEventDispatcher

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

Since version 18 is deprecated so I consider that it is a problem because in my case I am in version 31 and events like the ones I mention are still not migrated.: https://docs.nextcloud.com/server/latest/developer_manual/basics/events.html#hooks

The signal_update / signal_post_update signals of FileSystem are not subscribed to by HookConnector:

https://github.com/nextcloud/server/blob/9e0e53707f02c455bb5998130d0556ade7ca298f/lib/private/Files/Node/HookConnector.php#L46

Places where they are issued:

https://github.com/search?q=repo%3Anextcloud%2Fserver%20signal_update&type=code

https://github.com/search?q=repo%3Anextcloud%2Fserver+signal_post_update&type=code

In my case the one that interests me the most is this one because there is no way to find out when a file has been updated through IEventDispatcher other than NodeWrittenEvent which occurs in many use cases not only when you update the file:

https://github.com/nextcloud/server/blob/9e0e53707f02c455bb5998130d0556ade7ca298f/apps/dav/lib/Connector/Sabre/File.php#L435

Bonus: these uses of HookConnector should use FileSystem constants:

https://github.com/nextcloud/server/blob/9e0e53707f02c455bb5998130d0556ade7ca298f/lib/private/Files/Node/HookConnector.php#L46

Steps to reproduce

There is nothing to reproduce, in the code examples I put above you can see it clearly.

Expected behavior

There should be an event through IEventDispatcher in which you learn that a node has been changed.

Nextcloud Server version

31

Operating system

None

PHP engine version

None

Web server

None

Database engine version

None

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

List of activated Apps

Nextcloud Signing status

Nextcloud Logs

Additional info

No response

Start with lib/private/Files/Node/HookConnector.php and the signal_update and signal_post_update emissions linked in the issue, then inspect apps/dav/lib/Connector/Sabre/File.php around the referenced update path. Determine how these FileSystem signals should be represented through IEventDispatcher without relying on NodeWrittenEvent. Done means the relevant file-update events are dispatched and the HookConnector references FileSystem constants where appropriate.