fix: update GitHub Actions to latest versions and add security permissions

- Update actions/setup-python from v4 to v5
- Update peter-evans/create-pull-request from v5 to v7
- Add minimal permissions block (contents: write, pull-requests: write) for improved security

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: niechen

.github/workflows/generate-llm-txt.yml

@@ -19,6 +19,9 @@ on:
 jobs:
   generate-llm-txt:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
 
     steps:
     - name: Checkout code
@@ -28,7 +31,7 @@ jobs:
         fetch-depth: 0
 
     - name: Set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v5
       with:
         python-version: '3.11'
 
@@ -63,7 +66,7 @@ jobs:
 
     - name: Create Pull Request (for releases)
       if: github.event_name == 'release' && steps.check_changes.outputs.no_changes == 'false'
-      uses: peter-evans/create-pull-request@v5
+      uses: peter-evans/create-pull-request@v7
       with:
         token: ${{ secrets.GITHUB_TOKEN }}
         commit-message: "docs: update llm.txt for release ${{ github.event.release.tag_name }}"