`ATTACH 'datatable://main'` (or any datatable schema/executor path) failed
with a bare "datatable main not found", giving the user no way forward — the
datatable substrate has no auto-provisioning like a DuckLake catalog, so the
fix is always to create one in workspace settings, but nothing said so.
`get_datatable_resource_from_db_unchecked` now returns a NotFound error that
lists the workspace's configured data tables (to catch typos) and points at
the "Data tables" settings tab, noting `main` is the default name used by
`datatable://main`. The message bubbles up wherever the resolver is called
(pipeline ATTACH, schema fetch, postgres executor, agent HTTP endpoint).
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>