fix: settle anonymous single-file reservations

migrations/022_anonymous_single_reservations.sql

@@ -0,0 +1,20 @@
+CREATE TABLE anonymous_single_reservations (
+  task_id UUID PRIMARY KEY,
+  session_id VARCHAR(100) NOT NULL,
+  client_ip INET NOT NULL,
+  quota_date DATE NOT NULL,
+  units INTEGER NOT NULL,
+  status VARCHAR(20) NOT NULL DEFAULT 'pending',
+  refund_after TIMESTAMPTZ NOT NULL DEFAULT (NOW() + INTERVAL '15 minutes'),
+  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  settled_at TIMESTAMPTZ,
+  CONSTRAINT anonymous_single_reservations_units_check
+    CHECK (units > 0),
+  CONSTRAINT anonymous_single_reservations_status_check
+    CHECK (status IN ('pending', 'charged', 'refund_pending', 'refunded'))
+);
+
+CREATE INDEX anonymous_single_reservations_unsettled
+  ON anonymous_single_reservations(refund_after, created_at)
+  WHERE status IN ('pending', 'refund_pending');