* remove ChainingOp
* typos and other minor fixes
* remove Op, ChainingOp, flatten to CycleOp, derive RunnableOp
* refactor qdrant for aligned op types
* refactor mongodb for aligned op types
* refactor cqld4 for aligned op types
* minor API alignment
refactor gcpspanner for aligned op types
* minor API alignment
refactor gcpspanner for aligned op types
add license
* fix cqld4 batch statement mapper
* fix cql base op mapper
* remove var inference
* remove emitter for runnable op