fix: rename root package to beanflows-pipeline to avoid workspace conflict

The web package is already named 'beanflows'. Renaming the root CLI/infra
package to 'beanflows-pipeline' (src/beanflows_pipeline/) resolves the
uv workspace name conflict and Python namespace collision.

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

src/beanflows_pipeline/__init__.py

@@ -0,0 +1,2 @@
+def main() -> None:
+    print("Hello from beanflows!")