fix: use latest wfctl instead of go.mod version (v0.51.7 has no binary asset)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: intel352

.github/workflows/wfctl-validate.yml

@@ -25,19 +25,9 @@ jobs:
             exit 1
           fi
 
-      - uses: actions/setup-go@v5
-        with:
-          go-version-file: go.mod
-
-      - name: Derive wfctl version from go.mod
-        id: wfctl-ver
-        run: |
-          ver=$(go list -m -f '{{.Version}}' github.com/GoCodeAlone/workflow)
-          echo "version=$ver" >> "$GITHUB_OUTPUT"
-
       - uses: GoCodeAlone/setup-wfctl@bcd880980f5bbe8d192d0c20ff6279d25331f956
         with:
-          version: ${{ steps.wfctl-ver.outputs.version }}
+          version: latest
           token: ${{ secrets.RELEASES_TOKEN }}
 
       - name: Validate strict plugin contracts