bug fixes

backend/src/database/migrations/019_add_wiederholung.sql

@@ -0,0 +1,12 @@
+-- Migration 019: Add recurring event support
+-- Adds wiederholung (recurrence) config and parent link for generated instances
+
+ALTER TABLE veranstaltungen
+  ADD COLUMN IF NOT EXISTS wiederholung JSONB,
+  ADD COLUMN IF NOT EXISTS wiederholung_parent_id UUID REFERENCES veranstaltungen(id) ON DELETE SET NULL;
+
+CREATE INDEX IF NOT EXISTS idx_veranstaltungen_parent_id
+  ON veranstaltungen(wiederholung_parent_id);
+
+COMMENT ON COLUMN veranstaltungen.wiederholung IS 'JSON config for recurring events: {typ, intervall?, bis, wochentag?}';
+COMMENT ON COLUMN veranstaltungen.wiederholung_parent_id IS 'Links generated recurrence instances back to the parent event';