Improved Configuration and YAML Management (#2966)

# Description of Changes

**What was changed:**
- **Configuration Updates:**  
Replaced all calls to `GeneralUtils.saveKeyToConfig` with the new
`GeneralUtils.saveKeyToSettings` method across multiple classes (e.g.,
`LicenseKeyChecker`, `InitialSetup`, `SettingsController`, etc.). This
update ensures consistent management of configuration settings.
  
- **File Path and Exception Handling:**  
Updated file path handling in `SPDFApplication` by creating `Path`
objects from string paths and logging these paths for clarity. Also
refined exception handling by catching more specific exceptions (e.g.,
using `IOException` instead of a generic `Exception`).

- **Analytics Flag and Rate Limiting:**  
Changed the analytics flag in the application properties from a `String`
to a `Boolean`, and updated related logic in `AppConfig` and
`PostHogService`. The rate-limiting property retrieval in `AppConfig`
was also refined for clarity.

- **YAML Configuration Management:**  
Replaced the previous manual, line-based YAML merging logic in
`ConfigInitializer` with a new `YamlHelper` class. This helper leverages
the SnakeYAML engine to load, update, and save YAML configurations more
robustly while preserving comments and formatting.

**Why the change was made:**
- **Improved Maintainability:**  
Consolidating configuration update logic into a single utility method
(`saveKeyToSettings`) reduces code duplication and simplifies future
maintenance.
  
- **Enhanced Robustness:**  
The new `YamlHelper` class ensures that configuration files are merged
accurately and safely, minimizing risks of data loss or format
corruption.
  
- **Better Type Safety and Exception Handling:**  
Switching the analytics flag to a Boolean and refining exception
handling improves code robustness and debugging efficiency.
  
- **Clarity and Consistency:**  
Standardizing file path handling and logging practices enhances code
readability across the project.

**Challenges encountered:**
- **YAML Merging Complexity:**  
Integrating the new `YamlHelper` required careful handling to preserve
existing settings, comments, and formatting during merges.
  
- **Type Conversion and Backward Compatibility:**  
Updating the analytics flag from a string to a Boolean required
extensive testing to ensure backward compatibility and proper
functionality.
  
- **Exception Granularity:**  
Refactoring exception handling from a generic to a more specific
approach involved a detailed review to cover all edge cases.

Closes #<issue_number>

---

## Checklist

- [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
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [x] 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.

---------

Co-authored-by: Anthony Stirling <77850077+Frooodle@users.noreply.github.com>

src/main/java/stirling/software/SPDF/SPDFApplication.java

@@ -83,17 +83,18 @@ public class SPDFApplication {
         Map<String, String> propertyFiles = new HashMap<>();
 
         // External config files
-        String settingsPath = InstallationPathConfig.getSettingsPath();
-        log.info("Settings file: {}", settingsPath);
-        if (Files.exists(Paths.get(settingsPath))) {
-            propertyFiles.put("spring.config.additional-location", "file:" + settingsPath);
+        Path settingsPath = Paths.get(InstallationPathConfig.getSettingsPath());
+        log.info("Settings file: {}", settingsPath.toString());
+        if (Files.exists(settingsPath)) {
+            propertyFiles.put(
+                    "spring.config.additional-location", "file:" + settingsPath.toString());
         } else {
-            log.warn("External configuration file '{}' does not exist.", settingsPath);
+            log.warn("External configuration file '{}' does not exist.", settingsPath.toString());
         }
 
-        String customSettingsPath = InstallationPathConfig.getCustomSettingsPath();
-        log.info("Custom settings file: {}", customSettingsPath);
-        if (Files.exists(Paths.get(customSettingsPath))) {
+        Path customSettingsPath = Paths.get(InstallationPathConfig.getCustomSettingsPath());
+        log.info("Custom settings file: {}", customSettingsPath.toString());
+        if (Files.exists(customSettingsPath)) {
             String existingLocation =
                     propertyFiles.getOrDefault("spring.config.additional-location", "");
             if (!existingLocation.isEmpty()) {
@@ -101,9 +102,11 @@ public class SPDFApplication {
             }
             propertyFiles.put(
                     "spring.config.additional-location",
-                    existingLocation + "file:" + customSettingsPath);
+                    existingLocation + "file:" + customSettingsPath.toString());
         } else {
-            log.warn("Custom configuration file '{}' does not exist.", customSettingsPath);
+            log.warn(
+                    "Custom configuration file '{}' does not exist.",
+                    customSettingsPath.toString());
         }
         Properties finalProps = new Properties();
 
@@ -154,7 +157,7 @@ public class SPDFApplication {
                     } else if (os.contains("nix") || os.contains("nux")) {
                         SystemCommand.runCommand(rt, "xdg-open " + url);
                     }
-                } catch (Exception e) {
+                } catch (IOException e) {
                     log.error("Error opening browser: {}", e.getMessage());
                 }
             }