feat(jobs): improve scheduled tasks with retry logic and queue cleanup

- Add retry configuration to CoolifyTask (3 tries, 600s timeout)
- Add retry configuration to ScheduledTaskJob (3 tries, configurable timeout)
- Add retry configuration to DatabaseBackupJob (2 tries)
- Implement exponential backoff for all jobs (30s, 60s, 120s intervals)
- Add failed() handlers with comprehensive error logging to scheduled-errors channel
- Add execution tracking: started_at, retry_count, duration (decimal), error_details
- Add configurable timeout field to scheduled tasks (60-3600s, default 300s)
- Update UI to include timeout configuration in task creation/editing forms
- Increase ScheduledJobManager lock expiration from 60s to 90s for high-load environments
- Implement safe queue cleanup with restart vs runtime modes
  - Restart mode: aggressive cleanup (marks all processing jobs as failed)
  - Runtime mode: conservative cleanup (only marks jobs >12h as failed, skips deployments)
- Add cleanup:redis --restart flag for system startup
- Integrate cleanup into Dev.php init() for development environment
- Increase scheduled-errors log retention from 7 to 14 days
- Create comprehensive test suite (unit and feature tests)
- Add TESTING_GUIDE.md with manual testing instructions

Fixes issues with jobs failing after single attempt and "attempted too many times" errors

app/Jobs/ScheduledJobManager.php

@@ -52,7 +52,7 @@ class ScheduledJobManager implements ShouldQueue
     {
         return [
             (new WithoutOverlapping('scheduled-job-manager'))
-                ->expireAfter(60)   // Lock expires after 1 minute to prevent stale locks
+                ->expireAfter(90)   // Lock expires after 90s to handle high-load environments with many tasks
                 ->dontRelease(),    // Don't re-queue on lock conflict
         ];
     }