style(spotless): centralize and expand formatting config in root build.gradle (#4098)

# Description of Changes

- Removed redundant `spotless` configurations from `app/common`,
`app/core`, and `app/proprietary` modules.
- Consolidated all formatting logic into the root `build.gradle` file.
- Extended Spotless support to include:
  - YAML files (`*.yml`, `*.yaml`)
  - Gradle scripts (`*.gradle`, including nested `app/**/*.gradle`)
- Updated `googleJavaFormatVersion` from `1.27.0` to `1.28.0`.

This change improves maintainability by enforcing consistent formatting
across all modules from a single location. Additionally, it ensures
formatting is applied to Gradle and YAML files, which were previously
unformatted.

---

## 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/build.gradle

@@ -4,8 +4,7 @@ bootRun {
 }
 spotless {
     java {
-        target sourceSets.main.allJava
-        target sourceSets.test.allJava
+        target 'src/**/java/**/*.java'
         googleJavaFormat(googleJavaFormatVersion).aosp().reorderImports(false)
 
         importOrder("java", "javax", "org", "com", "net", "io", "jakarta", "lombok", "me", "stirling")
@@ -14,6 +13,18 @@ spotless {
         leadingTabsToSpaces()
         endWithNewline()
     }
+    yaml {
+        target '**/*.yml', '**/*.yaml'
+        trimTrailingWhitespace()
+        leadingTabsToSpaces()
+        endWithNewline()
+    }
+    format 'gradle', {
+        target '**/gradle/*.gradle', '**/*.gradle'
+        trimTrailingWhitespace()
+        leadingTabsToSpaces()
+        endWithNewline()
+    }
 }
 dependencies {
     api 'org.springframework.boot:spring-boot-starter-web'

app/core/build.gradle

@@ -14,8 +14,7 @@ configurations {
 
 spotless {
     java {
-        target sourceSets.main.allJava
-        target sourceSets.test.allJava
+        target 'src/**/java/**/*.java'
         googleJavaFormat(googleJavaFormatVersion).aosp().reorderImports(false)
 
         importOrder("java", "javax", "org", "com", "net", "io", "jakarta", "lombok", "me", "stirling")
@@ -24,6 +23,18 @@ spotless {
         leadingTabsToSpaces()
         endWithNewline()
     }
+    yaml {
+        target '**/*.yml', '**/*.yaml'
+        trimTrailingWhitespace()
+        leadingTabsToSpaces()
+        endWithNewline()
+    }
+    format 'gradle', {
+        target '**/gradle/*.gradle', '**/*.gradle'
+        trimTrailingWhitespace()
+        leadingTabsToSpaces()
+        endWithNewline()
+    }
 }
 
 dependencies {

app/proprietary/build.gradle

@@ -5,9 +5,8 @@ bootRun {
     enabled = false
 }
 spotless {
-    java {
-        target sourceSets.main.allJava
-        target sourceSets.test.allJava
+        java {
+        target 'src/**/java/**/*.java'
         googleJavaFormat(googleJavaFormatVersion).aosp().reorderImports(false)
 
         importOrder("java", "javax", "org", "com", "net", "io", "jakarta", "lombok", "me", "stirling")
@@ -16,6 +15,18 @@ spotless {
         leadingTabsToSpaces()
         endWithNewline()
     }
+    yaml {
+        target '**/*.yml', '**/*.yaml'
+        trimTrailingWhitespace()
+        leadingTabsToSpaces()
+        endWithNewline()
+    }
+    format 'gradle', {
+        target '**/gradle/*.gradle', '**/*.gradle'
+        trimTrailingWhitespace()
+        leadingTabsToSpaces()
+        endWithNewline()
+    }
 }
 dependencies {
     implementation project(':common')