feat: #3612486 Switch the default ECA modeler from BPMN.iO to the Workflow Modeler

Switches the Varbase Content Base recipe's default ECA editor from BPMN.iO to the Workflow Modeler (React Flow based).

Closes #3612486: Switch the default ECA modeler from BPMN.iO to the Workflow Modeler.

What changed

• recipe.yml: enable modeler instead of bpmn_io in the install list.
• composer.json: require drupal/modeler (~1.0) instead of drupal/bpmn_io (~3).
• config/eca.eca.enable_full_view_mode_node_type.yml: retag to modeler_id: workflow_modeler.
• config/eca.eca.redirect_403_to_login.yml: retag to modeler_id: workflow_modeler and drop the BPMN.iO raw data: 'hash:...' property (no longer needed — the diagram is re-derived from the config entity).
• Deleted config/modeler_api.data_model.eca_bpmn_io_redirect_403_to_login.yml (the companion BPMN 2.0 XML raw-data config object, no longer shipped).

bpmn_io stays available as a transitive dependency of eca for sites that still want it; it is simply no longer enabled by this recipe.

How it was tested

Verified live: 13 legacy BPMN.iO-authored models render correctly in the Workflow Modeler with 0 console errors; uninstalling bpmn_io afterwards leaves 0 leftover config; ECA still executes normally. grep -riE 'bpmn_io|bpmn-io' over the changed files on this branch returns no matches.

AI-Generated: Yes — this patch was prepared with AI assistance (Claude Code), per the Drupal policy on the use of AI when contributing to Drupal.

Checkpoints

• File an issue about this project
• Addition/Change/Update/Fix to this project
• Testing to ensure no regression
• Automated unit/functional testing coverage
• Developer Documentation support on feature change/addition
• User Guide Documentation support on feature change/addition
• UX/UI designer responsibilities
• Accessibility and Readability
• Reviewed by a human
• Code review by maintainers
• Full testing and approval
• Credit contributors
• Review with the product owner
• Update Release Notes
• Release