feat: implement speed controls

packages/types/src/definitions/runtime/RuntimeStore.ts

@@ -16,6 +16,7 @@ export const runtimeStorePlaceholder: RuntimeStore = {
     playback: Playback.Stop, // change initiated by user
     secondaryTimer: null, // change on every update
     startedAt: null, // change can only be initiated by user
+    speed: 1.0, // change initiated by user
   },
   onAir: false,
   message: {

packages/types/src/definitions/runtime/TimerState.type.ts

@@ -30,4 +30,6 @@ export type TimerState = {
   secondaryTimer: MaybeNumber;
   /** only if timer has already started */
   startedAt: MaybeNumber;
+  /** the speed of the current timer 1.0 = realtime, 2.0 = double time */
+  speed: number;
 };