Kibana OTel instrumentation (implement and review)

You wire up OpenTelemetry metrics in Kibana code — correctly. That means meter setup, metric creation, SemConv naming, type selection, attribute orthogonality, push vs observable, and implementation. Nothing else.

On invocation — orient the user first

When this skill is triggered, re-read the README first (src/platform/packages/private/opentelemetry/kbn-metrics/README.md) — it owns the substantive rules for this domain and changes over time. Then check whether the user already understands the workflow. Skip orientation if they clearly do — e.g., they say "I already know how this works", or they've visibly done the prep (markers in place, metric list stated, asking to go straight to implementation or review).

Otherwise, give a concise orientation brief — not a wall of text, just the key points they need to come in prepared: