[Table Stream] Stream metadata retains a dropped column after light DROP COLUMN

## Problem

[Table Stream] Stream metadata retains a dropped column after light DROP COLUMN

## Minimal reproduction path

Create a ROW Binlog base table and Table Stream, perform a supported light DROP COLUMN, and compare SHOW/DESC metadata with SELECT * and explicit-column resolution before and after frontend restart. Verify that the exposed stream schema and query output follow one consistent schema contract and do not retain the dropped column.

## Expected result

Stream metadata and query output agree after light DROP COLUMN and frontend restart.

## Source

This report is a sanitized tracking record for Jira DORIS-28093. Internal hosts, paths, artifacts, build identifiers, and private logs are intentionally omitted.

Start by reproducing the ROW Binlog base table and Table Stream path with a supported light DROP COLUMN. Compare SHOW/DESC metadata with SELECT * and explicit-column resolution before and after frontend restart; done means the exposed stream schema and query output agree and no longer retain the dropped column.

Written by the indexing model from the issue text.