Resolves #36087 (one of several small PRs). - [x] QA'd all new/changed functionality manually <!-- This is an auto-generated comment: release notes by coderabbit.ai --> ## Summary by CodeRabbit * **Refactor** * Reorganized internal API session models for improved code structure and maintainability. <!-- review_stack_entry_start --> [](https://app.coderabbit.ai/change-stack/fleetdm/fleet/pull/45908?utm_source=github_walkthrough&utm_medium=github&utm_campaign=change_stack) <!-- review_stack_entry_end --> <!-- end of auto-generated comment: release notes by coderabbit.ai -->