Make build_demo optional, skip demo-less datasets in tests

[mmcdermott]

Summary

Prerequisite for the per-dataset registration PRs (#305 AUMCdb, #306 EHRShot, #307 HIRID, #308 INSPIRE, #309 NWICU, #310 SICdb, #311 eICU). Most of those datasets' upstream extractors don't ship a publicly-installable demo, and the existing registry validation requires every dataset to declare a build_demo command.

Switches the convention to: a dataset has a demo iff its commands declare build_demo. The absence of the key is itself the signal — no separate metadata field, no echo "..." stubs, and no two-sources-of-truth ambiguity.

What changes

Three small edits, no behavior change for datasets that already declare build_demo (e.g., MIMIC-IV):

• test_all_datasets_have_commands now requires build_full (which every dataset still needs) and allows missing build_demo.
• tests/conftest.py drops datasets without build_demo from the integration test matrix, so a per-dataset CI lane for one collects zero parametrized tests and passes cleanly rather than trying to build data the dataset can't produce.
• src/MEDS_DEV/datasets/__main__.py raises a clear ValueError when called with demo=True against a dataset that doesn't declare a build_demo command (instead of the previous KeyError).

No dataset.yaml files change here — those changes ship with the sister per-dataset PRs that depend on this one.

Test plan

• Pre-commit passes.
• Fast test suite passes (53 tests, including the existing registry validation against MIMIC-IV).
• N/A: no new doctests; the logic is exercised by registry validation + the per-dataset integration lanes.

Refs

• Carved out of the closed bundled PR Add six new datasets (EHRShot, HIRID, INSPIRE, NWICU, SICdb, eICU) + complete AUMCdb #299.
• Each of Complete the AUMCdb dataset registration #305 – Add the eICU dataset #311 retargets to dev once this lands.

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 60.00000% with 2 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/MEDS_DEV/datasets/__main__.py	60.00%	2 Missing ⚠️

Files with missing lines	Coverage Δ
src/MEDS_DEV/datasets/__main__.py	92.30% <60.00%> (-7.70%)	⬇️