- Make cache fields private, add get_user_roles_in_space and
get_room_requirements_in_space accessor methods for admin layer
- Add flush_space_from_cache and call it when cascading is disabled
for a space (prevents stale enforcement data)
- Fix err!(Err("...")) -> err!("...") (redundant variant wrapper)
- Fix variable naming: sender -> server_user in ensure_default_roles
- Fix UFCS turbofish in validate_pl_change to simpler .as_str()
- Import Semaphore instead of inline tokio::sync::Semaphore path
- Add power_level bounds validation in add command (Matrix Int range)
- Add room-is-child-of-space validation in require command
- Handle SPACE_CASCADING_EVENT_TYPE in enforcement dispatch to flush
cache when a space is disabled