xframe fix new (#5580)

# Description of Changes

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## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

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- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

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### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
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app/core/src/main/resources/settings.yml.template

@@ -81,6 +81,7 @@ security:
     revocation:
       mode: none # Revocation checking mode: 'none' (disabled), 'ocsp' (OCSP only), 'crl' (CRL only), 'ocsp+crl' (OCSP with CRL fallback)
       hardFail: false # Fail validation if revocation status cannot be determined (true=strict, false=soft-fail)
+  xFrameOptions: DENY # X-Frame-Options header value. Options: 'DENY' (default, prevents all framing), 'SAMEORIGIN' (allows framing from same domain), 'DISABLED' (no X-Frame-Options header sent). Note: automatically set to DISABLED when login is disabled
 
 premium:
   key: 00000000-0000-0000-0000-000000000000