Add initial keyboard shortcut support.

src/card-controller/actions/utils/time-delta.ts

@@ -0,0 +1,10 @@
+import { TimeDelta } from '../../../config/types';
+
+export const timeDeltaToSeconds = (timeDelta: TimeDelta): number => {
+  return (
+    (timeDelta.h ?? 0) * 3600 +
+    (timeDelta.m ?? 0) * 60 +
+    (timeDelta.s ?? 0) +
+    (timeDelta.ms ?? 0) / 1000
+  );
+};