ci: add CI and CD workflows for pi-agent-plugin (#5469)

.github/workflows/cd.yml

@@ -7,7 +7,9 @@ on:
 jobs:
   build-n-publish:
     name: Build and publish Python 🐍 distributions 📦 to PyPI and TestPyPI
-    if: startsWith(github.event.release.tag_name, 'v')
+    # Pure SDK version tags only (v1.2.3) — excludes package-prefixed tags
+    # like vercel-ai-v* that also start with 'v'
+    if: startsWith(github.event.release.tag_name, 'v') && !contains(github.event.release.tag_name, '-v')
     runs-on: ubuntu-latest
     permissions:
       id-token: write
@@ -39,7 +41,7 @@ jobs:
       #     packages_dir: dist/
 
       - name: Publish distribution 📦 to PyPI
-        if: startsWith(github.ref, 'refs/tags/v')
+        if: startsWith(github.ref, 'refs/tags/v') && !contains(github.ref, '-v')
         uses: pypa/gh-action-pypi-publish@release/v1
         with:
           packages_dir: dist/