fix(ci): install golangci-lint v2.1.6 manually to match local environment

Install v2.1.6 manually in CI (not via action) to avoid --out-format flag
compatibility issues. This ensures both local and CI use the same version
and support version: 2 config format.

.github/workflows/ci.yml

@@ -78,9 +78,9 @@ jobs:
         with:
           go-version: '1.24'
 
-      - name: Install golangci-lint
+      - name: Install golangci-lint v2.1.6
         run: |
-          curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.64.8
+          curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v2.1.6
           echo "$(go env GOPATH)/bin" >> $GITHUB_PATH
 
       - name: Run golangci-lint