-- ImageHub: link a dataset to a research project (the "workspace" superstructure). Nullable,
-- so existing datasets stay unlinked and a dataset can still exist standalone. A dataset created
-- from a project cockpit attaches to that project. ON DELETE SET NULL so deleting a project
-- orphans its datasets rather than dropping the imaging data. Idempotent. Apply after 023
-- (no semicolons inside comments or string literals — the runner splitter is naive):
--   docker exec -i initiative-postgres psql -U initiative -d initiatives < be0/migrations/024_imagehub_dataset_project_link.sql

ALTER TABLE imagehub_datasets
  ADD COLUMN IF NOT EXISTS research_project_id UUID REFERENCES research_projects(id) ON DELETE SET NULL;

-- "Datasets in this project" lookup (the project-scoped dataset list).
CREATE INDEX IF NOT EXISTS idx_imagehub_datasets_research_project
  ON imagehub_datasets (research_project_id);