Reverts the PARTITION BY name change — group is the correct dedup key.
Partitioning by name broke country deduplication (two US records both
survived, causing Svelte each_key_duplicate on alpha_2_code='US').
Root cause is bad seed data in lu_v3_time_zone: group='United States'
for 13 US/* zones and group='Europe' for 63 Europe/* zones instead of
group=name. A separate DB UPDATE is required to fix those rows.
Tests updated to assert:
- No duplicate alpha_2_code in country list (PARTITION BY group regression)
- All 13 US/* and Europe/* spot-check zones present (pending DB data fix)
- priority-only timezone count == 72 (pending DB data fix)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>