feat: #3615987 Add the Varbase E2E automated functional testing suite

Adds the automated functional testing suite for Horizon Aid, built on @vardot/varbase-e2e (Playwright + Cucumber-js) — the harness every other Vardot site template and Varbase project runs on. Issue: #3615987.

Three suites, using only the harness's built-in steps (no custom step definitions to maintain):

• 01-website-base-requirements — every shipped canvas page (Home, About, Resources, Programs, Events, Countries, Donate) renders for an anonymous visitor; the main navigation and footer name and reach every section; the social profile links are visible.
• 02-editorial — the webmaster reaches the content listing, the media library and the page form.
• 03-permissions — anonymous visitors are denied every administrative surface; the login form renders.

CI follows the Educare pattern: composer validate + YAML lint + cspell + ESLint + a Cucumber dry-run in validate, then one browser job per suite in test (build a Varbase 11 project, install the Horizon Aid recipe, serve, drive with Playwright, publish the HTML + PDF report as artifacts).

All 27 scenarios resolve against the harness's step catalog with zero undefined and zero ambiguous steps (validated with a local dry-run).

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