ops(sentry): add a GBFM service-health dashboard and actionable alerts

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Production evidence

There are no custom dashboards. GET /api/profile/:username reached a 45.5% failure rate over 24 hours without a route-level alert. The active error monitor has no assignee.

Acceptance criteria

• Create a GBFM dashboard covering request volume, route failure rate, p95 latency, db failures/latency, logs, release regressions, and key routes.
• Add route failure-rate and latency alerts with noise-resistant thresholds.
• Route issue and metric alerts to an explicit owner.
• Use release-regression/error KPIs instead of treating backend process sessions as user crash-free health.
• Verify dashboard queries return production data and alerts are active.

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OPS-141

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Live progress: created GBFM Service Health with request volume, route outcomes/p95 latency, database failures/latency, error logs, errors by release, and key routes. The existing high-priority rule now explicitly owns issues to #goosebumps-collective and is throttled to five minutes. Sentry rejects metric-alert creation with You do not have permission to perform this action, so route failure-rate/latency alerts remain blocked and this issue stays open.

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Review follow-up: Sentry’s current Explore API extrapolates span aggregates by default; sampled raw counts are only returned when disableAggregateExtrapolation=1, which the dashboard does not request. The request-volume widgets therefore represent estimated request volume rather than unadjusted sampled-event counts. Dashboard #8960391 is still live; permission-blocked metric alerts remain the reason this issue stays open.

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Post-deploy status for v2.76.6: dashboard #8960391 is live and now receives production request, application, and safe db.query data. The dashboard side of the task is complete.

Keeping this open because Sentry still rejects creation/enabling of the route failure-rate and latency alerts with a permission error. Those alerts and explicit alert ownership remain the acceptance gap.