fix: upgrade GitHub Actions to v4 and remove invalid input

- actions/checkout@v2 → v4
- peaceiris/actions-hugo@v2 → v3
- peaceiris/actions-gh-pages@v3 → v4
- Remove invalid allow_deploy_from_same_branch input

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ZhuoranYang

.github/workflows/gh-pages.yml

@@ -3,20 +3,20 @@ name: Deploy to GitHub Pages
 on:
   push:
     branches:
-      - source  # Trigger on changes to the source branch
+      - source
   workflow_dispatch:
 
 jobs:
   build:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout source code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
-          ref: source  # Check out the source branch
+          ref: source
 
       - name: Setup Hugo
-        uses: peaceiris/actions-hugo@v2
+        uses: peaceiris/actions-hugo@v3
         with:
           hugo-version: 'latest'
 
@@ -27,9 +27,8 @@ jobs:
         run: touch ./public/.nojekyll
 
       - name: Deploy to GitHub Pages
-        uses: peaceiris/actions-gh-pages@v3
+        uses: peaceiris/actions-gh-pages@v4
         with:
           personal_token: ${{ secrets.PERSONAL_TOKEN }}
           publish_dir: ./public
-          publish_branch: main  # Deploy built files to main branch
-          allow_deploy_from_same_branch: true
+          publish_branch: main