ci: 修复GitHub Actions权限和rebase问题

.github/workflows/subset-fonts.yml

@@ -35,6 +35,8 @@ jobs:
     name: Subset Fonts
     runs-on: ubuntu-latest
     timeout-minutes: 30
+    permissions:
+      contents: write  # 添加写权限
 
     # 只在主仓库上运行（fork不运行）
     if: github.repository == 'zqlit/blog'