seeding expansion

also: replace energy output with energy output density

tests/test_pipeline_async.py

@@ -21,9 +21,12 @@ def test_pipeline_run_lifecycle(seeded_repo):
 
     pipeline.run(domain, ["platform", "power_source"], passes=[1, 2, 3], run_id=run_id)
 
+    from physcom.seed.transport_example import PLATFORMS, POWER_SOURCES
+    expected = len(PLATFORMS) * len(POWER_SOURCES)
+
     run = repo.get_pipeline_run(run_id)
     assert run["status"] == "completed"
-    assert run["total_combos"] == 81
+    assert run["total_combos"] == expected
     assert run["started_at"] is not None
     assert run["completed_at"] is not None