New package com.cameleer3.server.core.rbac with SystemRole constants,
detail/summary records, GroupRepository, RoleRepository, RbacService.
Remove roles field from UserInfo. Implement PostgresGroupRepository,
PostgresRoleRepository, RbacServiceImpl with inheritance computation.
Update UiAuthController, OidcAuthController, AgentRegistrationController
to assign roles via user_roles table. JWT populated from effective system roles.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>