ci: pin golangci-lint to v2.11.2 for Go 1.25 compatibility

Author: edouard-claude

.github/workflows/ci.yaml

@@ -35,6 +35,8 @@ jobs:
           go-version-file: go.mod
 
       - uses: golangci/golangci-lint-action@v6
+        with:
+          version: v2.11.2
 
   vulncheck:
     runs-on: ubuntu-latest