fix(mimic-iv): retain device-only rows in oxygen_delivery

[acnimma]

Summary

• Filter O2 flow rn in ce_stg3 before the FULL OUTER JOIN in oxygen_delivery.sql
• Retain device-only charttimes (itemid 226732) that previously disappeared when WHERE ce.rn = 1 ran after the join
• Regenerate postgres and duckdb dialect copies from the BigQuery source

Test plan

• pytest tests/test_transpile.py -k oxygen_delivery passes locally
• CI concept build on MIMIC-IV demo

oxygen_delivery FULL OUTER JOINs O2 flow (ce_stg2) with delivery devices (o2, itemid 226732), then applied WHERE ce.rn = 1. That filter drops rows where ce is NULL, so stays with device charting but no flow (e.g. stay_id = 30813912 in #1570) never appear in the derived table. Move the rn = 1 filter into ce_stg3 before the join so device-only rows are kept. Regenerate postgres and duckdb dialect copies from the BigQuery source.

Fixes #1570

[Chessing234]

the post-join where ce.rn = 1 was definitely nuking device-only rows from the full outer join — moving the rn filter into ce_stg3 first is the right shape. coalesce on subject/stay/charttime was already there so device-only keys should survive. if you haven't already, worth a quick count of rows where o2_flow is null but o2_delivery_device_1 isn't, before vs after.

[Chessing234]

keeping device-only oxygen rows is useful for vent studies. does the regenerated postgres/duckdb copy land in this pr too?

[Chessing234]

filtering rn before the full outer join is the right fix — post-join where ce.rn = 1 was dropping device-only o2 rows when ce was null. mirrored across dialects; the comment in the bq file helps. a tiny regression query in concepts/documentation (device-only count before/after) would make the behavioral change obvious to reviewers.