fix(ci): install golangci-lint manually and remove version field

The golangci-lint-action has compatibility issues with v2.1.6 (uses
--out-format flag which v2 doesn't support). Install golangci-lint manually
to avoid action limitations and remove version field from config to be
compatible with CI v1.64.8. Local v2.x will work but may show warnings.

.github/workflows/ci.yml

@@ -78,11 +78,13 @@ jobs:
         with:
           go-version: '1.24'
 
+      - name: Install golangci-lint
+        run: |
+          curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.64.8
+          echo "$(go env GOPATH)/bin" >> $GITHUB_PATH
+
       - name: Run golangci-lint
-        uses: golangci/golangci-lint-action@v3
-        with:
-          version: v1.64.8
-          args: --timeout=5m
+        run: golangci-lint run --timeout=5m
 
   build:
     name: Build

.golangci.yml

@@ -1,7 +1,7 @@
 # golangci-lint configuration
 # See https://golangci-lint.run/usage/configuration/
-# Note: CI uses v1.64.8 which doesn't support version: 2
-# Local v2.x will work with this config but may show a deprecation warning
+# Note: No version field - compatible with both v1.64.8 (CI) and v2.x (local)
+# Local v2.x may show a deprecation warning but will work
 
 run:
   timeout: 5m