feat: Add RBAC environment roles API support

[csrbarber]

Summary

• Add resource_type_slug field to Role resource
• Add environment role endpoints to RBAC module: createEnvironmentRole, listEnvironmentRoles, getEnvironmentRole, updateEnvironmentRole, setEnvironmentRolePermissions, addEnvironmentRolePermission
• Update OrganizationsTest role fixtures to include resource_type_slug

Part 2 of 3 for RBAC support. Stacked on #337.

Test plan

• 6 new tests covering each environment role endpoint
• All existing tests pass (including updated Organization role fixtures)

🤖 Generated with Claude Code

[linear]

ENT-4805 workos-php

[greptile-apps]

Greptile Summary

This PR adds RBAC environment role API support to the WorkOS PHP SDK with six new methods on the RBAC class (createEnvironmentRole, listEnvironmentRoles, getEnvironmentRole, updateEnvironmentRole, setEnvironmentRolePermissions, addEnvironmentRolePermission) and a new resource_type_slug field on the Role resource. It is the second part of a three-part RBAC implementation.

The implementation follows existing patterns, all six methods are covered by tests, and the changes are straightforward and correct.

Confidence Score: 5/5

• Safe to merge with high confidence. Implementation is correct and well-tested.
• All code changes are straightforward, follow established patterns in the codebase, and are covered by comprehensive tests. The new methods align with the existing API and resource structure. No security, functionality, or consistency issues identified.
• No files require special attention

Important Files Changed

Filename	Overview
lib/RBAC.php	Adds 6 environment role API methods with correct implementation following existing patterns established by permission endpoints. All methods are straightforward implementations without issues.
lib/Resource/Role.php	Correctly adds resource_type_slug to the allowed attributes and response mapping. Straightforward and consistent with the existing resource pattern.
tests/WorkOS/RBACTest.php	6 new tests comprehensively cover all added endpoints. Fixtures are properly structured and tests correctly verify the expected behavior.
tests/WorkOS/OrganizationsTest.php	Updated role fixtures to include the new resource_type_slug field. Changes are minimal and correct.

_{Last reviewed commit: 9c0f184}