add updateDocuments(Term, ColumnBatch) to IndexWriter for atomic delete-and-add columnar operations

experimental columnar indexing API (`IndexWriter.addBatch(ColumnBatch)`) added supports bulk columnar document addition, but there is no equivalent to `updateDocuments(Term, Iterable)`
for columnar batches. Users who index via columns cannot atomically delete existing documents by term
and add a new columnar batch in a single operation.

add the following public methods to `IndexWriter`

```java
/**
* Atomically deletes documents matching the provided term and adds a batch of documents
* in column-oriented format.
*/
public long updateDocuments(Term delTerm, ColumnBatch columnBatch) throws IOException;

/**
* Similar to above but takes a Query instead of a Term.
*/
public long updateDocuments(Query delQuery, ColumnBatch columnBatch) throws IOException;

Start in the IndexWriter entry point, comparing the existing updateDocuments overloads with addBatch(ColumnBatch). Trace how term- and query-based deletion is combined with columnar batch addition, then verify that both new overloads preserve atomic delete-and-add behavior and return the expected result.

Written by the indexing model from the issue text.