feat(n8n): add KEDA ScaledObject for worker autoscaling

[h0lybyte]

Summary

• Add TriggerAuthentication referencing existing n8n-redis-secret for KEDA Redis auth
• Add ScaledObject targeting n8n-worker Deployment based on Bull queue depth (n8n-bull:jobs:wait in Redis DB 2)
• Scales 1–5 replicas, polls every 15s, 5min cooldown before scale-down
• Activates scaling when ≥1 job is waiting, targets 5 jobs per replica

Details

• KEDA operator is already live on the cluster (PR feat(kube): add KEDA event-driven autoscaler operator #7605)
• Redis key n8n-bull:jobs:wait is a List (Bull's waiting queue), matching KEDA's redis (lists) scaler
• databaseIndex: 2 matches QUEUE_BULL_REDIS_DB=2 from n8n deployment
• All manifests pass kubectl apply --dry-run=client

Closes last open item from #7590 (KEDA-based worker scaling)

Test plan

• Verify TriggerAuthentication and ScaledObject sync via ArgoCD
• Confirm KEDA operator can reach Redis DB 2 and read queue length
• Trigger test workflows to queue jobs, observe worker replica scaling
• Verify scale-down after cooldown period (300s)

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Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

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