feat: refresh computed columns (#3938)

table.refresh_column("doubled") fills the rows of a declared column that
hold no value, in two passes per fragment: the first scans only the
unfilled
live rows to count exact gains and decide staging, the second streams
the
fragment's physical rows into a standalone column file published in one
DataReplacement -- committed under the dataset's own session -- so peak
memory is bounded by a scan batch. A row that holds a value keeps it;
deleted and already-filled rows never reach the expression, so a poison
value in them cannot fail the refresh. Refresh refuses under an LSM
write
spec, including the mem-wal catch-up flag that outlives unset and marks
retained SSTable rows.

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docs/src/js/interfaces/RefreshColumnResult.md

@@ -0,0 +1,23 @@
+[**@lancedb/lancedb**](../README.md) • **Docs**
+
+***
+
+[@lancedb/lancedb](../globals.md) / RefreshColumnResult
+
+# Interface: RefreshColumnResult
+
+## Properties
+
+### rowsFilled
+
+```ts
+rowsFilled: number;
+```
+
+***
+
+### version
+
+```ts
+version: number;
+```