Reduce SQLite contention from OpenTelemetry SDK debug logs

[zanie-oai]

Summary

• skip opentelemetry_sdk DEBUG and TRACE events before formatting or queueing them for the SQLite log sink
• preserve INFO, WARN, and ERROR events from the SDK, along with TRACE events from application targets
• add a persistence-level regression test for the target and level policy

Why

OpenTelemetry's batch log processor emits internal BatchLogProcessor.ExportingDueToTimer meta-events every second per Codex process. In measured high-fanout logs_2.sqlite databases, low-level opentelemetry_sdk events accounted for over 30% of retained rows (30-60% on the machines of people I asked to check).

Persisting this SDK bookkeeping across many processes adds substantial write volume and contention without representing application activity.

Validation

• just test -p codex-state (132/132 tests passed, plus bench smoke)
• just fix -p codex-state
• just fmt

[zanie-oai]

I'm hoping to reduce the number of concurrent app-servers separately, e.g., with changes to the Codex application, but these logs don't seem worthwhile anyway.

[zanie-oai]

I think the number reported is a bit high — I'll see if I can get some more samples.

[zanie-oai]

I had two other people check volume and they had 35% and 55% respectively.