PR: Data Retention

Summary

• Add plan-based trace retention windows.
• Add tracing retention DAO/service and admin endpoint to flush old spans.
• Add cron entry to trigger retention runs.

Scope

• EE tracing retention (plans and billing endpoint).
• Core/OSS migrations for retention-related indexes.
• UI exposure of retention settings.

QA: Data Retention

Functional checks

• Verify logs show per-plan retention cutoff and deletion counts.
• Confirm old traces are removed and newer traces remain.

Edge cases

• No projects for a plan (should log skip/zero counts).
• Unlimited retention (plan should be skipped).
• Large batch sizes (ensure job completes under cron timeout).

Monitoring

• Check logs for flush start/end markers.
• Track DB load during retention run.