System Settings Tests (new file):
- Create system_settings_test.go with comprehensive test coverage
- Test admin-only access control
- Test validation (15-1440 minute range)
- Test error handling scenarios
- Test integration with scheduler
User Tests Cleanup:
- Remove old TestScanSettings from user_test.go
- Scan settings moved to system-wide (no longer per-user)
Device Cap Tests Enhancement:
- Update TestListUsersIncludesMaxDevices
- Add assertion for device_count field
- Verify both max_devices and device_count in response
All tests verify the migration from per-user to system-wide scan settings.
