chore: add GitHub Actions workflow to sync all upstream branches from xixu-me/Xget

.github/workflows/upstream-sync.yml

@@ -0,0 +1,45 @@
+name: Sync Upstream Branches
+
+on:
+  schedule:
+    - cron: '0 0 * * *'
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}
+  cancel-in-progress: false
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Configure Git
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+      - name: Add upstream remote
+        run: |
+          git remote add upstream https://github.com/xixu-me/Xget.git
+
+      - name: Fetch all upstream branches
+        run: |
+          git fetch upstream
+
+      - name: Sync all upstream branches
+        run: |
+          for branch in $(git branch -r | grep 'upstream/' | grep -v 'HEAD' | sed 's|upstream/||'); do
+            echo "Syncing branch: $branch"
+            git checkout -B "$branch" "upstream/$branch"
+            git push origin "$branch" --force
+          done