* docs: add KreuzbergConverter documentation page
* docs: address PR review comments for KreuzbergConverter
Remove Kreuzberg from external integrations page since it lives in
core integrations. Add explanation of how token reduction works using
TF-IDF-based extractive summarization with approximate reduction
percentages per level.
* docs: add KreuzbergConverter page to version 2.26 stable docs
Copy the KreuzbergConverter documentation page, converters index
entry, and sidebar entry to the 2.26 versioned docs so the page
appears in the current stable version.
Varun Tandon
27ff1266b5