feat: ARIA Roles & Properties für CookiePolicy implementiert (#144)

[PeachpitRipley]

• Added role="dialog", aria-modal, aria-labelledby, aria-describedby to the CookiePolicy modal
• Connected ARIA attributes to title and description via IDs
• implemented focus trap behavior using keyboard navigation (Tab loop)
• Unit tests for visibility, interaction and cookie state
• E2E-Test with Playwright: focus, click, reload, route exception

Description

Implements ARIA roles and properties for the CookiePolicy component to improve accessibility and keyboard usability. Includes tests for expected behavior and edge cases as described in ticket #144.

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Translation updates (fix/improve or add new translations)

Note on commit history

The long list of commits was cleaned up by the last two commits:

1. chore: Fix test and lint setup...: Bundles all necessary corrections to the test environment (dependencies, CJS/ESM conflict, mock corrections) that were needed to restore pipeline functionality.
2. feat(a11y): Implement accessible...: Contains only the pure feature code.

All tests (unit/E2E/lint) are now green on the CI server.

Fixes Bootstrap-Academy/Bootstrap-Academy#144

My Bootstrap Academy username: PeachpitRipley