[danoswaltCL]

adds "perfdiag" stats events as a custom event that can be piped directly to new relic instead of using logging.

https://docs.newrelic.com/docs/data-apis/custom-data/custom-events/report-custom-event-data/

this will allow us to query it all in NR, and obviate the need for the app that I created to marry the splunk logs with new relic data.

i'm leaving the logging for now, but that could be removed later if this works.

[Copilot]

🟢 Approval recommended

The additive telemetry preserves existing logging, enablement controls, and failure isolation, with no blocking issues identified.

No open issues 🎉

What changed in this PR

Adds New Relic custom events for backend performance diagnostics, allowing metrics to be queried alongside transaction data while retaining existing JSON logging and enablement controls.

Changes:

• Emits PerfDiag window reports and PerfDiagCacheWrite slow-write events.
• Flattens nested event attributes and omits null values through a failure-isolated New Relic wrapper.
• Adds tests for event payloads, missing fields, and slow-write thresholds.

File	Description
packages/​backend/​test/​unit/​lib/​perfDiagnostics.test.ts	Tests event emission, flattened attributes, and threshold behavior.
packages/​backend/​src/​lib/​perfDiagnostics.ts	Emits custom events alongside existing diagnostic logs.
packages/​backend/​src/​lib/​newrelic.ts	Adds a guarded custom-event API wrapper.
packages/​backend/​src/​env.ts	Removes “Temporary” from the diagnostics comment; no behavior change.
packages/​backend/​src/​api/​services/​CacheService.ts	Clarifies the cache-write instrumentation comment; no behavior change.

_{Review effort: Balanced}

[bcb37]

interesting