docs: align jwt-auth README with public API

[gustavomarques00]

Summary

Aligns README with the current public package API after protectWithRoles was exported.

Changes

• Adds role-based authorization to the package description and recruiter summary.
• Adds middleware.protectWithRoles(roles) to the public API reference table.
• Adds a role-based route usage example.
• Removes outdated note saying protectWithRoles was not part of the public API.
• Updates roadmap to mark role middleware as exported.

Validation

Documentation-only change.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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