limit PR diff size and filter control characters

- Limit the diff to the first 10.000 lines
- Filter out problematic control characters

.github/workflows/ai_pr_title_review.yml

@@ -66,7 +66,7 @@ jobs:
         id: get_diff
         run: |
           git fetch origin ${{ github.base_ref }}
-          git diff origin/${{ github.base_ref }}...HEAD > pr.diff
+          git diff origin/${{ github.base_ref }}...HEAD | head -n 10000 | grep -vP '[\x00-\x08\x0B\x0C\x0E-\x1F\x7F\x{202E}\x{200B}]' > pr.diff
           echo "diff<<EOF" >> $GITHUB_OUTPUT
           cat pr.diff >> $GITHUB_OUTPUT
           echo "EOF" >> $GITHUB_OUTPUT