init push

migrations/20260504_duty_roster_drop_unique_base_date.sql

@@ -0,0 +1,9 @@
+-- Allow multiple duty roster headers on the same base and duty date.
+-- Previous schema enforced unique(base_id, duty_date) via idx_roster_base_date.
+
+ALTER TABLE duty_rosters
+  DROP INDEX idx_roster_base_date;
+
+CREATE INDEX idx_roster_base_date
+  ON duty_rosters (base_id, duty_date);
+