patterndetectorprocessor: promote operator-facing scalar attrs onto verdict records

[trilamsr]

Problem

PR #264 (Grafana dashboard) review found that 4 of 7 dashboard panels render empty against current patterndetectorprocessor output. Verdict log records carry only:

• pattern.id
• pattern.headline
• pattern.remediation
• pattern.verdict_json (the full marshalled verdict)
• pattern.confidence (pod_evicted only)

Operator-facing fields are buried INSIDE pattern.verdict_json (e.g. Regarding.Name, HangingRanks, EvictedPod). Dashboards can't table-aggregate by pod/node/collective without server-side JSON parsing — fragile.

Proposed fix

Promote operator-facing scalar fields to top-level OTLP log-record attributes in appendVerdict / appendNCCLHangVerdict / appendXidCorrelationVerdict:

• pod_evicted ([docs] FOLLOWUPS: close squash-merge-trailer item with observation #14): k8s.pod.name, k8s.pod.namespace, k8s.node.name, k8s.event.reason
• nccl_hang ([telemetry] Add SelfTelemetry interface + agent infra scaffolding #15): nccl.fr.pg_id, nccl.fr.collective_seq_id, nccl.fr.hanging_ranks_count
• xid_correlation ([receivers] Add kernelevents receiver (dmesg + journald, alpha) #16): kernelevents.xid, k8s.node.name, k8s.pod.name, k8s.pod.namespace

Each detector already has these values in its verdict struct; just PutStr them onto the log record alongside the existing VerdictAttr* calls. Constant naming: VerdictAttrK8sPodName etc. — extend the existing taxonomy in patterndetector.go:25-44.

Acceptance

• LogQL queries on {cluster=~"...", pattern_id="14"} | json reach the scalar attrs at top level (no | line_format JSON parse).
• Dashboard PR feat(dashboards): grafana JSON for pattern verdicts #264 panels 2/3/4/5 render populated tables on fixture input.
• pattern.verdict_json REMAINS — it's the canonical full payload for advanced operators.
• New verdict-shape regression tests pin the attribute set.

Related

• PR feat(dashboards): grafana JSON for pattern verdicts #264 blocked on this — dashboards render empty without it
• Issue patterndetectorprocessor: emit verdict counter metric for dashboard panels #261 (processor counter metrics) is independent; both close v0.3 dashboard story
• PR-A (DCGM→hw.* recipe + metrics-input ADR) is independent — doesn't touch verdict-emission path