feat(release): guard empty notes and recommend next tag

.gitea/workflows/push-validation.yml

@@ -121,3 +121,26 @@ jobs:
       - name: Run behavior suite on main pushes
         if: ${{ github.ref == 'refs/heads/main' }}
         run: ./script/run-behavior-suite-docker.sh
+
+      - name: Recommend next release tag on main pushes
+        if: ${{ github.ref == 'refs/heads/main' }}
+        run: |
+          set -euo pipefail
+
+          if recommended_tag="$(go run ./cmd/releaseprep --recommend --root . 2>release-recommendation.err)"; then
+            {
+              echo
+              echo '## Release Recommendation'
+              echo
+              echo "- Recommended next tag: \\`${recommended_tag}\\`"
+            } >> "$GITHUB_STEP_SUMMARY"
+          else
+            recommendation_error="$(tr '\n' ' ' < release-recommendation.err | sed 's/[[:space:]]\+/ /g' | sed 's/^ //; s/ $//')"
+            echo "::warning::${recommendation_error}"
+            {
+              echo
+              echo '## Release Recommendation'
+              echo
+              echo "- No recommended tag emitted: ${recommendation_error}"
+            } >> "$GITHUB_STEP_SUMMARY"
+          fi