**Related issue:** Resolves#45220 (one of many small PRs)
## Testing
- [x] QA'd all new/changed functionality manually. (Ran basic smoke
testing.)
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## Summary by CodeRabbit
* **Tests**
* Added a consolidated test utilities package to boot full test servers,
seed users, retrieve auth tokens, and provide common mocks for
integration/service tests.
* Updated integration and service tests to use the new helpers for more
consistent, reliable test setup and wiring.
* **Chores**
* Centralized and reorganized test configuration types and options, and
standardized test wiring for clearer, maintainable test setup.
[](https://app.coderabbit.ai/change-stack/fleetdm/fleet/pull/45221)
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