Add sync-versions job to GitHub Actions workflow (#5228)

# Description of Changes

This pull request updates the `.github/workflows/build.yml` file to
improve automation and consistency in the build process. The most
significant change is the addition of a new `sync-versions` job that
automatically checks for and synchronizes version differences across key
files, and posts a comment on the pull request if mismatches are
detected. Additionally, there are minor formatting updates for
consistency.

**Automation and version synchronization:**

* Added a new `sync-versions` job that runs after the build, checks for
version mismatches between `build.gradle` and several frontend files,
and posts or updates a comment on the pull request to notify
contributors if differences are found. This job uses a GitHub App bot
for authentication and ensures that versioning remains consistent across
the project.

**Formatting consistency:**

* Updated the YAML formatting for `node-version`, `cache`, and
`python-version` fields to use double quotes for consistency in the
`build.yml` workflow.
[[1]](diffhunk://#diff-5c3fa597431eda03ac3339ae6bf7f05e1a50d6fc7333679ec38e21b337cb6721L150-R151)
[[2]](diffhunk://#diff-5c3fa597431eda03ac3339ae6bf7f05e1a50d6fc7333679ec38e21b337cb6721L244-R338)


<img width="1127" height="401" alt="image"
src="https://github.com/user-attachments/assets/6930a72d-f72b-4909-97e2-51f0e0f61613"
/>


---

## 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)

### 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.

.github/workflows/build.yml

@@ -196,6 +196,104 @@ jobs:
           path: frontend/dist/
           retention-days: 3
 
+  sync-versions:
+    if: needs.files-changed.outputs.build == 'true'
+    needs: [files-changed, build]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@f4a75cfd619ee5ce8d5b864b0d183aff3c69b55a # v2.13.1
+        with:
+          egress-policy: audit
+
+      - name: Checkout repository
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+        with:
+          fetch-depth: 0
+
+      - name: Setup GitHub App Bot
+        id: setup-bot
+        uses: ./.github/actions/setup-bot
+        with:
+          app-id: ${{ secrets.GH_APP_ID }}
+          private-key: ${{ secrets.GH_APP_PRIVATE_KEY }}
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@dded0888837ed1f317902acf8a20df0ad188d165 # v5.0.0
+        with:
+          java-version: "21"
+          distribution: "temurin"
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@4d9f0ba0025fe599b4ebab900eb7f3a1d93ef4c2 # v5.0.0
+        with:
+          gradle-version: 8.14
+
+      - name: Run version sync
+        run: ./gradlew syncAppVersion --build-cache
+
+      - name: Check if version files have changed
+        id: git-check
+        run: |
+          if [[ -n $(git status --porcelain) ]]; then
+            echo "changes=true" >> $GITHUB_OUTPUT
+          else
+            echo "changes=false" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Post comment on PR
+        if: steps.git-check.outputs.changes == 'true' && github.event_name != 'workflow_dispatch'
+        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+        with:
+          github-token: ${{ steps.setup-bot.outputs.token }}
+          script: |
+            const { GITHUB_REPOSITORY } = process.env;
+            const [repoOwner, repoName] = GITHUB_REPOSITORY.split('/');
+            const issueNumber = context.issue.number;
+
+            // Find existing comment
+            const comments = await github.rest.issues.listComments({
+              owner: repoOwner,
+              repo: repoName,
+              issue_number: issueNumber
+            });
+
+            const comment = comments.data.find(c => c.body.includes("## ⚠️ Version Differences"));
+
+            const commentBody = `## ⚠️ Version Differences
+
+            The versions in the following files do not match the version defined in \`build.gradle\`.
+
+            Running \`./gradlew syncAppVersion\` or \`./gradlew build\` will automatically update these files:
+
+            \`frontend/src-tauri/tauri.conf.json\`, \`frontend/src/proprietary/testing/serverExperienceSimulations.ts\`, \`frontend/src/core/testing/serverExperienceSimulations.ts\`
+
+            Please run \`./gradlew syncAppVersion\` or \`./gradlew build\`!`;
+
+            // Only update or create comments by the action user
+            const expectedActor = "${{ steps.setup-bot.outputs.app-slug }}[bot]";
+
+            if (comment && comment.user.login === expectedActor) {
+              // Update existing comment
+              await github.rest.issues.updateComment({
+                owner: repoOwner,
+                repo: repoName,
+                comment_id: comment.id,
+                body: commentBody
+              });
+              console.log("Updated existing comment.");
+            } else if (!comment) {
+              // Create new comment if no existing comment is found
+              await github.rest.issues.createComment({
+                owner: repoOwner,
+                repo: repoName,
+                issue_number: issueNumber,
+                body: commentBody
+              });
+            } else {
+              console.log("Comment update attempt denied. Actor does not match.");
+            }
+
   check-licence:
     if: needs.files-changed.outputs.build == 'true'
     needs: [files-changed, build]