Add a Reminder subtype and dispatch an Event, when a timestamp was passed.

Is your feature request related to a problem? Please describe.

As a user I would like to have a special DateTime field that dispatches something like a ReminderEvent when the specified date and time was passed, so that another arbitrary app may listen and react to it.

Describe the solution you'd like

• add a "reminder" (better name possible)
• register a background job that will execute at that time
• the background job will dispatch a typed Event
• the Event includes the following data:
  • acting user (who created/updated the column)
  • the Table
  • the Row
  • the Column
  • the Cell
  • the Event is json-serializable, the objects are reduced to their id
• also possible nice-to-have: visual color-based indicator when there is "enough" time until that date (green), it is close to that timestamp (yellow) or when it is reached and passed (red). To be discussed with design, but not critical for this feature.

Describe alternatives you've considered

No response

Additional context

This is required for the upcoming workflow engine efforts.

Start by locating the existing DateTime field implementation, background-job patterns, and typed event dispatch code in the repository. Define the reminder field and job around the requested timestamp, then verify that the event carries the acting user, table, row, column, and cell as IDs and is JSON-serializable. The color indicator is optional and not required for completion.