Creates minimal .jsonl.gz and .json.gz seed files so all SQLMesh staging
models can compile and run before real extraction data arrives.
Each seed has a single null record filtered by the staging model's WHERE
clause (tenant_id IS NOT NULL, geoname_id IS NOT NULL, type IS NOT NULL, etc).
Covers both formats (JSONL + blob) for the UNION ALL transition CTEs:
playtomic/1970/01/: tenants.{jsonl,json}.gz, availability seeds (morning + recheck)
geonames/1970/01/: cities_global.{jsonl,json}.gz
overpass_tennis/1970/01/: courts.{jsonl,json}.gz
overpass/1970/01/: courts.json.gz (padel, unchanged format)
eurostat/1970/01/: urb_cpop1.json.gz, ilc_di03.json.gz
eurostat_city_labels/1970/01/: cities_codelist.json.gz
ons_uk/1970/01/: lad_population.json.gz
census_usa/1970/01/: acs5_places.json.gz
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>