Refactor codebase to replace explicit constructors with Lombok annotations and remove boilerplat (#3415)

# Description of Changes

- **What was changed:**  
- Removed explicit constructor definitions annotated with `@Autowired`
across services, controllers, filters, and schedulers.
- Added Lombok’s `@RequiredArgsConstructor` to automatically generate
required-args constructors and eliminate boilerplate.
- Introduced other Lombok annotations (`@Data`, `@Getter`, `@Setter`,
`@EqualsAndHashCode`, `@NoArgsConstructor`) on model and API classes to
replace manual getters/setters and constructors.
- Standardized string comparisons to use the constant-first form (e.g.,
`"value".equals(variable)`).
- Cleaned up unused imports and organized OpenAPI configuration by
extracting default title/description constants.

- **Why the change was made:**  
  - To reduce repetitive boilerplate code and improve maintainability.  
- To leverage Lombok for cleaner, more consistent dependency injection
and data modeling.
  - To ensure a uniform coding style across the entire codebase.

#3406

---

## Checklist

### General

- [x] 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/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/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/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached  

### Testing (if applicable)

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

src/main/java/stirling/software/SPDF/config/AppConfig.java

@@ -20,8 +20,7 @@ import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceLoader;
 import org.thymeleaf.spring6.SpringTemplateEngine;
 
-import com.posthog.java.shaded.kotlin.text.Regex;
-
+import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 
 import stirling.software.SPDF.model.ApplicationProperties;
@@ -29,14 +28,11 @@ import stirling.software.SPDF.model.ApplicationProperties;
 @Configuration
 @Lazy
 @Slf4j
+@RequiredArgsConstructor
 public class AppConfig {
 
     private final ApplicationProperties applicationProperties;
 
-    public AppConfig(ApplicationProperties applicationProperties) {
-        this.applicationProperties = applicationProperties;
-    }
-
     @Bean
     @ConditionalOnProperty(name = "system.customHTMLFiles", havingValue = "true")
     public SpringTemplateEngine templateEngine(ResourceLoader resourceLoader) {