fix: repair checklist create (intervall constraint) and start execution (stuck spinner), add equipment items display

backend/src/database/migrations/072_checklisten_intervall_fix.sql

@@ -0,0 +1,10 @@
+-- Migration 072: Fix checklist_vorlagen intervall CHECK constraint
+-- The original constraint in 068 was missing 'quarterly' and 'halfyearly'.
+-- These values are used in the frontend and service but were rejected by the DB.
+
+ALTER TABLE checklist_vorlagen
+  DROP CONSTRAINT IF EXISTS checklist_vorlagen_intervall_check;
+
+ALTER TABLE checklist_vorlagen
+  ADD CONSTRAINT checklist_vorlagen_intervall_check
+  CHECK (intervall IN ('weekly', 'monthly', 'quarterly', 'halfyearly', 'yearly', 'custom'));