task: #3620331 Remove the Varbase Dev Base recipe from composer.json

Issue: https://www.drupal.org/project/educare/issues/3620331

varbase_dev_base is a development recipe — it installs dblog, views_ui, config_update_ui, devel, sdc_devel and reroute_email — and educare never applies it: it is not in the recipes: list of recipe.yml.

Requiring it in composer.json made every Educare site download a development toolchain it never enables. Measured on a real Educare build, all seven packages are pulled and none is enabled on the installed site:

Package	Version	Enabled
drupal/varbase_dev_base	1.0.0-rc1	not applied
drupal/storybook	1.0.4	not enabled
drupal/devel	5.5.0	not enabled
drupal/sdc_devel	1.0.3	not enabled
drupal/stage_file_proxy	3.1.6	not enabled
drupal/reroute_email	2.3.0-rc2	not enabled
drupal/devel_entity_updates	5.0.0	not enabled

It also blocks installing the site template onto a plain Drupal CMS codebase, because varbase_dev_base requires drupal/storybook ~1.0:

drupal/storybook[1.0.0-alpha1, ..., 1.0.0-beta2] require drupal/core ^9 || ^10
  -> conflicts with your root composer.json require (^11.3.10).
drupal/storybook[1.0.0, ..., 1.x-dev] require symfony/css-selector ^4 || ^6 || ^7
  -> the package is fixed to v8.1.6 (lock file version) by a partial update.

This MR removes the single require entry. Nothing applies the recipe, so nothing depends on it. A developer who wants the tooling can require drupal/varbase_dev_base in their own project and apply it explicitly.

AI-Generated: Yes

Checkpoints:

• File an issue
• Addition/Change/Update/Fix
• Testing to ensure no regression
• Automated unit testing coverage
• Automated functional testing coverage
• UX/UI designer responsibilities
• Readability
• Accessibility
• Performance
• Security
• Developer Documentation
• User Guide Documentation
• Reviewed by human
• Code review by maintainers
• Full testing and approval
• Credit contributors
• Review with the product owner
• Release notes snippet
• Release