refactor(common, core, proprietary): migrate boxed Booleans to primitive booleans and adopt is* accessors to reduce null checks/NPE risk (#4153)

# Description of Changes

**What was changed**
- Switched multiple nullable `Boolean` fields to primitive `boolean` in
`ApplicationProperties`:
  - `Security.enableLogin`, `Security.csrfDisabled`
- `System.googlevisibility`, `System.showUpdateOnlyAdmin`,
`System.enableAlphaFunctionality`, `System.disableSanitize`,
`System.enableUrlToPDF`
  - `Metrics.enabled`
- Updated all consumers to use Lombok’s `is*` accessors instead of
`get*`:
- `AppConfig`, `PostHogService`, `CustomHtmlSanitizer`,
`EndpointConfiguration`, `InitialSetup`, `OpenApiConfig`,
`ConvertWebsiteToPDF`, `HomeWebController`, `MetricsController`,
proprietary `SecurityConfiguration`, `AccountWebController`
- Tests adjusted to mock `isDisableSanitize()` instead of
`getDisableSanitize()`
- Logic simplifications:
- Removed redundant null-handling/ternaries now that primitives have
defaults (e.g., `enableAlphaFunctionality` bean)
  - Replaced `Boolean.TRUE.equals(...)` with direct primitive checks
  - Used constant-first `equals` for NPE safety in string comparisons

**Why the change was made**
- Primitive booleans eliminate ambiguity, cut down on
`NullPointerException` risks, and simplify conditions
- Aligns with Java/Lombok conventions (`isX()` for `boolean`) for
clearer, more consistent APIs
- Spring provides sane defaults for missing booleans (`false`), reducing
boilerplate and cognitive load

---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] 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)
- [x] I have performed a self-review of my own code
- [x] 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)

### 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/configuration/AppConfig.java

@@ -70,7 +70,7 @@ public class AppConfig {
 
     @Bean(name = "loginEnabled")
     public boolean loginEnabled() {
-        return applicationProperties.getSecurity().getEnableLogin();
+        return applicationProperties.getSecurity().isEnableLogin();
     }
 
     @Bean(name = "appName")
@@ -120,9 +120,7 @@ public class AppConfig {
 
     @Bean(name = "enableAlphaFunctionality")
     public boolean enableAlphaFunctionality() {
-        return applicationProperties.getSystem().getEnableAlphaFunctionality() != null
-                ? applicationProperties.getSystem().getEnableAlphaFunctionality()
-                : false;
+        return applicationProperties.getSystem().isEnableAlphaFunctionality();
     }
 
     @Bean(name = "rateLimit")

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

@@ -112,8 +112,8 @@ public class ApplicationProperties {
 
     @Data
     public static class Security {
-        private Boolean enableLogin;
-        private Boolean csrfDisabled;
+        private boolean enableLogin;
+        private boolean csrfDisabled;
         private InitialLogin initialLogin = new InitialLogin();
         private OAUTH2 oauth2 = new OAUTH2();
         private SAML2 saml2 = new SAML2();
@@ -295,8 +295,8 @@ public class ApplicationProperties {
                                 throw new UnsupportedProviderException(
                                         "Logout from the provider "
                                                 + registrationId
-                                                + " is not supported. "
-                                                + "Report it at https://github.com/Stirling-Tools/Stirling-PDF/issues");
+                                                + " is not supported. Report it at"
+                                                + " https://github.com/Stirling-Tools/Stirling-PDF/issues");
                     };
                 }
             }
@@ -314,19 +314,19 @@ public class ApplicationProperties {
     @Data
     public static class System {
         private String defaultLocale;
-        private Boolean googlevisibility;
+        private boolean googlevisibility;
         private boolean showUpdate;
-        private Boolean showUpdateOnlyAdmin;
+        private boolean showUpdateOnlyAdmin;
         private boolean customHTMLFiles;
         private String tessdataDir;
-        private Boolean enableAlphaFunctionality;
+        private boolean enableAlphaFunctionality;
         private Boolean enableAnalytics;
         private Boolean enablePosthog;
         private Boolean enableScarf;
         private Datasource datasource;
-        private Boolean disableSanitize;
+        private boolean disableSanitize;
         private int maxDPI;
-        private Boolean enableUrlToPDF;
+        private boolean enableUrlToPDF;
         private Html html = new Html();
         private CustomPaths customPaths = new CustomPaths();
         private String fileUploadLimit;
@@ -453,10 +453,10 @@ public class ApplicationProperties {
         @Override
         public String toString() {
             return """
-                Driver {
-                  driverName='%s'
-                }
-                """
+            Driver {
+              driverName='%s'
+            }
+            """
                     .formatted(driverName);
         }
     }
@@ -491,7 +491,7 @@ public class ApplicationProperties {
 
     @Data
     public static class Metrics {
-        private Boolean enabled;
+        private boolean enabled;
     }
 
     @Data

app/common/src/main/java/stirling/software/common/service/PostHogService.java

@@ -253,11 +253,11 @@ public class PostHogService {
         addIfNotEmpty(
                 properties,
                 "security_enableLogin",
-                applicationProperties.getSecurity().getEnableLogin());
+                applicationProperties.getSecurity().isEnableLogin());
         addIfNotEmpty(
                 properties,
                 "security_csrfDisabled",
-                applicationProperties.getSecurity().getCsrfDisabled());
+                applicationProperties.getSecurity().isCsrfDisabled());
         addIfNotEmpty(
                 properties,
                 "security_loginAttemptCount",
@@ -302,13 +302,13 @@ public class PostHogService {
         addIfNotEmpty(
                 properties,
                 "system_googlevisibility",
-                applicationProperties.getSystem().getGooglevisibility());
+                applicationProperties.getSystem().isGooglevisibility());
         addIfNotEmpty(
                 properties, "system_showUpdate", applicationProperties.getSystem().isShowUpdate());
         addIfNotEmpty(
                 properties,
                 "system_showUpdateOnlyAdmin",
-                applicationProperties.getSystem().getShowUpdateOnlyAdmin());
+                applicationProperties.getSystem().isShowUpdateOnlyAdmin());
         addIfNotEmpty(
                 properties,
                 "system_customHTMLFiles",
@@ -320,7 +320,7 @@ public class PostHogService {
         addIfNotEmpty(
                 properties,
                 "system_enableAlphaFunctionality",
-                applicationProperties.getSystem().getEnableAlphaFunctionality());
+                applicationProperties.getSystem().isEnableAlphaFunctionality());
         addIfNotEmpty(
                 properties,
                 "system_enableAnalytics",
@@ -337,7 +337,7 @@ public class PostHogService {
 
         // Capture Metrics properties
         addIfNotEmpty(
-                properties, "metrics_enabled", applicationProperties.getMetrics().getEnabled());
+                properties, "metrics_enabled", applicationProperties.getMetrics().isEnabled());
 
         // Capture EnterpriseEdition properties
         addIfNotEmpty(

app/common/src/main/java/stirling/software/common/util/CustomHtmlSanitizer.java

@@ -62,8 +62,7 @@ public class CustomHtmlSanitizer {
                     .and(new HtmlPolicyBuilder().disallowElements("noscript").toFactory());
 
     public String sanitize(String html) {
-        boolean disableSanitize =
-                Boolean.TRUE.equals(applicationProperties.getSystem().getDisableSanitize());
+        boolean disableSanitize = applicationProperties.getSystem().isDisableSanitize();
         return disableSanitize ? html : POLICY.sanitize(html);
     }
 }