chore: Remove Go proxy setup from build workflow

- Eliminated the Go proxy configuration from the build workflow to streamline the setup process.
- This change simplifies the environment setup for dependency management.

.gitea/workflows/build.yml

@@ -23,12 +23,6 @@ jobs:
           go-version: '1.25'
           cache: false
 
-      - name: Set up Go Proxy
-        run: |
-          echo "GOPROXY=https://goproxy.cn,direct" >> $GITHUB_ENV
-          echo "GOSUMDB=off" >> $GITHUB_ENV
-          echo "已设置国内 Go 代理"
-
       - name: Download dependencies
         run: go mod download