fix(workflow): preserve newlines in ONLY_FILES for filenames with spaces

The previous workflow converted newlines to spaces using tr, but the
Python script splits by newlines. Filenames with spaces (e.g.,
'Introduction to Airflow in Python.md') were being parsed incorrectly.

Now ONLY_FILES preserves newline separation for proper parsing.

Author: ppippi-dev

.github/workflows/translate-to-english.yml

@@ -22,39 +22,45 @@ jobs:
       - name: Get changed blog posts
         id: changes
         run: |
-          POSTS=$(git diff --name-only HEAD~1 HEAD -- 'src/content/blog/*.md' | tr '\n' ' ')
-          echo "posts=$POSTS" >> $GITHUB_OUTPUT
-          echo "Changed posts: $POSTS"
+          POSTS=$(git diff --name-only HEAD~1 HEAD -- 'src/content/blog/*.md')
+          if [ -n "$POSTS" ]; then
+            echo "has_posts=true" >> $GITHUB_OUTPUT
+            echo "Changed posts:"
+            echo "$POSTS"
+          else
+            echo "has_posts=false" >> $GITHUB_OUTPUT
+            echo "No changed posts"
+          fi
 
       - name: Set ONLY_FILES env
-        if: steps.changes.outputs.posts != ''
+        if: steps.changes.outputs.has_posts == 'true'
         run: |
           echo 'ONLY_FILES<<EOF' >> $GITHUB_ENV
-          echo '${{ steps.changes.outputs.posts }}' >> $GITHUB_ENV
+          git diff --name-only HEAD~1 HEAD -- 'src/content/blog/*.md' >> $GITHUB_ENV
           echo 'EOF' >> $GITHUB_ENV
 
       - name: Set up Python
-        if: steps.changes.outputs.posts != ''
+        if: steps.changes.outputs.has_posts == 'true'
         uses: actions/setup-python@v5
         with:
           python-version: '3.11'
 
       - name: Install dependencies
-        if: steps.changes.outputs.posts != ''
+        if: steps.changes.outputs.has_posts == 'true'
         run: |
           python -m pip install --upgrade pip
           pip install openai PyYAML python-frontmatter
 
       - name: Generate English translations
-        if: steps.changes.outputs.posts != ''
+        if: steps.changes.outputs.has_posts == 'true'
         env:
           OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
           TRANSLATION_MODEL: ${{ vars.TRANSLATION_MODEL }}
         run: |
           python scripts/translate_to_en.py
 
       - name: Commit and push translations
-        if: steps.changes.outputs.posts != ''
+        if: steps.changes.outputs.has_posts == 'true'
         uses: stefanzweifel/git-auto-commit-action@v5
         with:
           commit_message: "chore: add English translations"