Tears down the in-memory DuckDB connection and clears cached metadata.
Non-connection state (e.g. extracted file paths) is preserved.
See also
Other Workbench management:
codeminer_clear_col_filters(),
codeminer_clear_versions(),
codeminer_connect(),
codeminer_refresh_cache(),
codeminer_set_col_filters(),
codeminer_set_version(),
codeminer_snapshot_extra(),
codeminer_status(),
default_col_filters(),
get_col_filters(),
with_col_filters()