- [X] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
## Testing
- [X] Added/updated automated tests
- [x] QA'd all new/changed functionality manually
<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit
* **Security Enhancements**
* Enforced strict size limits for SAMLResponse payloads and rejected
overly large submissions.
* Added protections against deeply nested or excessively large SAML XML
documents.
* Applied rate limiting to SSO/authentication callback endpoints
(configurable via Auth settings).
* **Tests**
* Added tests verifying SAMLResponse size and XML shape validation
behavior.
* **Documentation**
* Noted these SSO validation and rate-limiting changes in the changelog.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
Lucas Manuel Rodriguez
ac6aa7329c