feat(jobs): add cache-based deduplication for delayed cron execution

Implements getPreviousRunDate() + cache-based tracking in shouldRunNow()
to prevent duplicate dispatch of scheduled jobs when queue delays push
execution past the cron minute. This resilience ensures jobs catch missed
windows without double-dispatching within the same cron window.

Updated scheduled job dispatches to include dedupKey parameter:
- Docker cleanup operations
- Server connection checks
- Sentinel restart checks
- Server storage checks
- Server patch checks

DockerCleanupJob now dispatches on the 'high' queue for faster processing.

Includes comprehensive test coverage for dedup behavior across different
cron schedules and delay scenarios.

app/Jobs/DockerCleanupJob.php

@@ -39,7 +39,9 @@ class DockerCleanupJob implements ShouldBeEncrypted, ShouldQueue
         public bool $manualCleanup = false,
         public bool $deleteUnusedVolumes = false,
         public bool $deleteUnusedNetworks = false
-    ) {}
+    ) {
+        $this->onQueue('high');
+    }
 
     public function handle(): void
     {