fix: omit unfetchable list blobs from column discovery (#4312)

nodejs/lancedb/blob.ts

@@ -81,6 +81,8 @@ export type BlobOptions = {
  *
  * Query results are descriptors, not payload bytes. Use {@link Table.fetchBlobs}
  * or {@link Table.fetchBlobFiles} to read bytes.
+ * Blobs inside lists can be written and queried as descriptors, but cannot
+ * currently be fetched because a row ID does not identify a list element.
  *
  * @example
  * ```ts

nodejs/lancedb/table.ts

@@ -526,7 +526,8 @@ export abstract class Table {
   abstract takeRowIds(rowIds: readonly (bigint | number)[]): TakeQuery;
 
   /**
-   * Blob v2 columns, including nested dotted paths.
+   * Blob v2 columns addressable by row ID, including struct-nested dotted paths.
+   * Blobs inside lists are omitted because a row ID does not identify an element.
    */
   abstract blobColumns(): Promise<string[]>;
 
@@ -538,6 +539,8 @@ export abstract class Table {
    * duplicates. Null blobs are `null`. Empty blobs are empty buffers.
    * One missing or deleted row ID rejects the entire batch, including on remote
    * tables; no partial results are returned.
+   * Blobs inside lists cannot be fetched by row ID.
+   *
    * Remote servers limit each request to 1024 row IDs and 64 MiB of blob bytes.
    * The client splits requests automatically and reads an individual larger
    * blob through the Range route. This method still materializes all bytes in