fix(clerk-js): unset domain cookies

[jacekradko]

Description

Evaluating this change.. not ready for merge

Checklist

• [ ] pnpm test runs as expected.
• [ ] pnpm build runs as expected.
• [ ] (If applicable) JSDoc comments have been added or updated for any package exports
• [ ] (If applicable) Documentation has been updated

Type of change

• [ ] 🐛 Bug fix
• [ ] 🌟 New feature
• [ ] 🔨 Breaking change
• [ ] 📖 Refactoring / dependency upgrade / documentation
• [ ] other:

Summary by CodeRabbit

• New Features

  • Domain-aware session cookies for consistent behavior across subdomains and cross-origin contexts.
  • Improved cookie attributes (SameSite and partitioned) for better compatibility and security.

• Bug Fixes

  • Logout and session rotation now reliably clear stale cookies, including subdomain variants.
  • Prevents duplicate or lingering cookies by purging legacy non-domain cookies.

• Tests

  • Expanded tests to validate domain-specific set/remove flows and attribute handling across contexts.