fix(monitoring): remove legacy container and default empty cronJob - #5141

The swarm migration in 3848fa9c0 dropped the container.remove({force:true}) that the standalone deploy path used to run. Swarm tasks are named dokploy-monitoring.<slot>.<id>, so there is no name collision and the pre-v0.30.0 container survives every redeploy. It also stays pinned to an orphaned image ID once pullRemoteImage moves the latest tag, so neither a pull nor a Save clears it and it restarts forever.

Cloud setup spread metricsConfig straight from the row, shipping cronJob: "" to the agent. robfig/cron rejects an empty spec, so the Go binary exits before Fiber binds 4500 and Docker restarts it every ~60s.

• remove the legacy container in deployMonitoringService, which covers both setupMonitoring and setupWebMonitoring. Cleanup is best effort: a failure is logged and the deploy continues, matching the pre-migration behaviour
• default cronJob when configuring monitoring for cloud
• on build servers, clean up the legacy container but deploy no service. They never join the swarm, yet cloud setup did create the standalone container there before v0.30.0, and the monitoring form has always been hidden for them, so those agents are all stuck with an empty cronJob

What is this PR about?

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Checklist

Before submitting this PR, please make sure that:

• You created a dedicated branch based on the canary branch.
• You have read the suggestions in the CONTRIBUTING.md file https://github.com/Dokploy/dokploy/blob/canary/CONTRIBUTING.md#pull-request
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Greptile Summary

This PR removes legacy standalone monitoring containers before deploying the current Swarm service and supplies a default retention cron expression during cloud server setup.

• Adds best-effort cleanup for the legacy dokploy-monitoring container.
• Defaults an empty cloud monitoring cron expression to a daily schedule.
• Adds real-Docker coverage for legacy cleanup and service deployment.

Confidence Score: 5/5

The PR appears safe to merge because no eligible blocking failure remains from the provided follow-up-review context.

No blocking failure remains.

_{Reviews (3): Last reviewed commit: "mend" | Re-trigger Greptile}

Context used:

• Knowledge Base — Servers, clusters, and monitoring