feat: auto create empty schedule when deleted all schedules (#552)

* feat: enhance schedule deletion to create a new schedule if none remain

* feat: set active index to new schedule if only one exists

* chore: run lint

* feat: enhance schedule deletion to create a new schedule if none remain

* feat: set active index to new schedule if only one exists

* chore: run lint

* feat: reset schedules on update, refactor invariant to within deleteSchedule

* chore: pnpm lint

---------

Co-authored-by: Samuel Gunter <29130894+Samathingamajig@users.noreply.github.com>
Co-authored-by: Samuel Gunter <sgunter@utexas.edu>

src/pages/background/lib/deleteSchedule.ts

@@ -22,6 +22,11 @@ export default async function deleteSchedule(scheduleId: string): Promise<string
     schedules.splice(scheduleIndex, 1);
     await UserScheduleStore.set('schedules', schedules);
 
+    // By invariant, there must always be at least one schedule
+    if (schedules.length === 0) {
+        createSchedule('Schedule 1');
+    }
+
     let newActiveIndex = activeIndex;
     if (scheduleIndex < activeIndex) {
         newActiveIndex = activeIndex - 1;