fix: format hour display on Loop End screen to avoid floating-point precision errors

- Use formatHour() instead of raw {hour} to display time in HH:MM format
  (e.g. '15:00' instead of '14.999999999999998')
- Export formatHour from stores barrel index
- Fixes #336

src/lib/game/stores/index.ts

@@ -32,6 +32,7 @@ export type { GameCoordinatorStore } from './gameStore';
 export {
   fmt,
   fmtDec,
+  formatHour,
   getFloorMaxHP,
   getFloorElement,
   getFloorElements,