Pipeline visualization enhancements

[mbroecheler]

Improve the pipeline graph by showing materialized connectors more clearly—either on edges or within physical plan nodes - so users can visually trace how data flows and where it persists.

[mbroecheler]

We need to capture the various table materializations (and their unique ids) and put them on the edges in cytoscape.
This requires:

• an update to the EXPLAIN plan that includes these outputs
• an update to the graph visualization that puts those on the edges with side panel for the connector configuration: https://chatgpt.com/share/68409728-d8c4-8007-ac75-7c1f0542177b