Plan for Subentity 4.0.0

This issue tracks the plan for the 4.0.0 release of the Subentity module.

Miscellaneous

• #3609944: Drop Drupal 10 support and set Drupal 11.4 to minimum
• #3609949: Use PHP Attributes for route definition and discovery
• #3610248: Upgrade drupal-rector to 1.x to support Drupal12SetList

API & correctness

• #3593856: Add SubEntityInterface, getParent()/hasParent() methods, and parent_entity_type/parent_id base fields to SubEntityBase
• Add cascade delete via hook_entity_delete or EventSubscriber to clean up orphaned subentities (choose between a queueworker and a custom command both treated)

Bug fixes

• Fix truncated "Parent" column in ReferencedEntityListBuilder when a subentity has multiple parents

To be determined

• Add per-type and per-operation permissions (view, create, edit, delete) to replace the single administer subentities permission

Each item will be tracked in its own issue and linked here.