xframe fix new (#5580)

# Description of Changes

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- Why the change was made
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Closes #(issue_number)
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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)

### Translations (if applicable)

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

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

app/common/src/main/java/stirling/software/common/model/ApplicationProperties.java

@@ -164,6 +164,7 @@ public class ApplicationProperties {
         private String customGlobalAPIKey;
         private Jwt jwt = new Jwt();
         private Validation validation = new Validation();
+        private String xFrameOptions = "DENY";
 
         public Boolean isAltLogin() {
             return saml2.getEnabled() || oauth2.getEnabled();

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

app/proprietary/src/main/java/stirling/software/proprietary/security/configuration/SecurityConfiguration.java

@@ -201,6 +201,31 @@ public class SecurityConfiguration {
 
         http.csrf(CsrfConfigurer::disable);
 
+        // Configure X-Frame-Options based on settings.yml configuration
+        // When login is disabled, automatically disable X-Frame-Options to allow embedding
+        if (!loginEnabledValue) {
+            http.headers(headers -> headers.frameOptions(frameOptions -> frameOptions.disable()));
+        } else {
+            String xFrameOption = securityProperties.getXFrameOptions();
+            if (xFrameOption != null) {
+                http.headers(headers -> {
+                    if ("DISABLED".equalsIgnoreCase(xFrameOption)) {
+                        headers.frameOptions(frameOptions -> frameOptions.disable());
+                    } else if ("SAMEORIGIN".equalsIgnoreCase(xFrameOption)) {
+                        headers.frameOptions(frameOptions -> frameOptions.sameOrigin());
+                    } else {
+                        // Default to DENY
+                        headers.frameOptions(frameOptions -> frameOptions.deny());
+                    }
+                });
+            } else {
+                // If not configured, use default DENY
+                http.headers(headers ->
+                    headers.frameOptions(frameOptions -> frameOptions.deny())
+                );
+            }
+        }
+
         if (loginEnabledValue) {
 
             http.addFilterBefore(