fix(ci): remove @latest npm promotion from pipeline

Dev-stamped versions (2.28.0-dev.xxx) should never be promoted to
@latest on npm. Stable releases are handled by the publish-version
workflow. The pipeline promotes @dev → @next only.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/pipeline.yml

@@ -137,10 +137,8 @@ jobs:
           OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
           GSD_LIVE_TESTS: "1"
 
-      - name: Promote to @latest
-        run: npm dist-tag add gsd-pi@${{ needs.dev-publish.outputs.dev-version }} latest
-        env:
-          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
+      # NOTE: @latest promotion is handled by the publish-version workflow,
+      # not by the pipeline. Dev versions should never be tagged as @latest.
 
       - name: Log in to GHCR
         uses: docker/login-action@v3