feat(node): add blobMode to return blob bytes from queries - #4353

Closes #4187.

Node queries can now return blob bytes instead of descriptors. QueryExecutionOptions gets blobMode?: "descriptions" | "bytes", used by toArrow() and toArray():

const rows = await table.query().where("id = 1").toArray({ blobMode: "bytes" });
rows[0].image; // Uint8Array with the blob bytes

"descriptions" stays the default, so nothing changes for existing callers.

How it works

With "bytes", the query also reads _rowid, then fills each top-level blob v2 column with the bytes from fetchBlobs (as LargeBinary). _rowid stays out of the result unless the caller asked for it with withRowId(). Renamed columns work too, for example select(new Map([["picture", "image"]])). Blobs nested in a struct or a list keep their descriptors.

This is the same approach Python uses for blob v2. to_pandas(blob_mode="bytes") reads descriptors and _rowid, then swaps in the bytes via fetch_blobs (from #3578), and the plan agreed in #4186 does the same for to_arrow and to_list. I also looked at passing Lance's BlobHandling::AllBinary through the Rust query instead. I didn't go that way because QueryRequest and the remote query protocol have no field for it, so it would only work on local tables. Going through fetchBlobs works on remote tables as well, and it works for vector, full-text and take queries, not just plain scans.

Two details:

• The native query builder mutates the query in place, so calling withRowId() on the caller's query would leak _rowid into its later executions. Instead, native execute takes an optional withRowId flag that adds _rowid to a clone for that one execution.
• The bytes column is a new field, not a clone of the descriptor field, so the blob v2 marker from the descriptor doesn't carry over to a binary column.

To get at fetchBlobs, the query classes now carry the table they read (Query, VectorQuery, TakeQuery, and the AutoQuery behind search()). The TypeScript API is unchanged apart from the new option and the BlobMode type.

Tests

New tests in table.test.ts cover toArrow and toArray with blobMode: "bytes" (column type, no blob marker, nulls), _rowid only when requested, a renamed blob column, a take query, a second execution of the same query still returning descriptors and no _rowid, a selection with no blob column, an empty result, and an invalid blobMode. The whole Node suite passes. The Node docs under docs/src/js are regenerated.

A "lazy" mode that returns BlobFile handles could only work in toArray(), since Arrow can't hold JS objects, so I left it for later.