Right-click a column header in the data grid to copy the ALTER TABLE
statement for that column, making it easy to replicate column definitions
across databases. Supports all major dialects (MySQL, Postgres, SQL Server,
Oracle, ClickHouse, SQLite, DuckDB, H2).
Closes#516
Previously the sidebar tree refresh was skipped entirely in EDIT mode because
the check was gated on activeTab.mode === 'data', which is never true when
the structure editor is open. Now we pass a commentChanged flag through the
event chain and only refresh the tree when the comment was modified.
dbin0123