Add GitHub Actions workflow to sync fork from upstream

Author: sdsdsdff

.github/workflows/main.yml

@@ -0,0 +1,37 @@
+name: Sync fork from upstream
+
+on:
+  schedule:
+    - cron: "0 3 * * *"   # 每天 03:00 UTC，可改
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout fork
+        uses: actions/checkout@v4
+        with:
+          ref: main
+          fetch-depth: 0
+
+      - 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 and fetch
+        run: |
+          git remote add upstream https://github.com/TOZHR/grok2api.git
+          git fetch upstream
+
+      - name: Merge upstream/main into main
+        run: |
+          git merge --ff-only upstream/main || git merge upstream/main
+
+      - name: Push changes
+        run: |
+          git push origin main