feat(watchlist): Cache watchlist requests with matching E-Tags (#3901)

* perf(watchlist): add E-Tag caching to Plex watchlist requests

* refactor(watchlist): increase frequency of watchlist requests

* fix: sync watchlist every 3 min instead of 3 sec

server/job/schedule.ts

@@ -8,7 +8,6 @@ import type { JobId } from '@server/lib/settings';
 import { getSettings } from '@server/lib/settings';
 import watchlistSync from '@server/lib/watchlistsync';
 import logger from '@server/logger';
-import random from 'lodash/random';
 import schedule from 'node-schedule';
 
 interface ScheduledJob {
@@ -62,30 +61,20 @@ export const startJobs = (): void => {
   });
 
   // Watchlist Sync
-  const watchlistSyncJob: ScheduledJob = {
+  scheduledJobs.push({
     id: 'plex-watchlist-sync',
     name: 'Plex Watchlist Sync',
     type: 'process',
-    interval: 'fixed',
+    interval: 'seconds',
     cronSchedule: jobs['plex-watchlist-sync'].schedule,
-    job: schedule.scheduleJob(new Date(Date.now() + 1000 * 60 * 20), () => {
+    job: schedule.scheduleJob(jobs['plex-watchlist-sync'].schedule, () => {
       logger.info('Starting scheduled job: Plex Watchlist Sync', {
         label: 'Jobs',
       });
       watchlistSync.syncWatchlist();
     }),
-  };
-
-  // To help alleviate load on Plex's servers, we will add some fuzziness to the next schedule
-  // after each run
-  watchlistSyncJob.job.on('run', () => {
-    watchlistSyncJob.job.schedule(
-      new Date(Math.floor(Date.now() + 1000 * 60 * random(14, 24, true)))
-    );
   });
 
-  scheduledJobs.push(watchlistSyncJob);
-
   // Run full radarr scan every 24 hours
   scheduledJobs.push({
     id: 'radarr-scan',