Tasks — logger-spec-conformance

Add **Verified by:** line under every LG-NN requirement in openspec/specs/logging/spec.md.
Add src/abstract/abstract-logger.spec-conformance.test.ts covering LG-12 OTel instrumentation and LG-20 tree-shake safety.
Confirm bun scripts/openspec-conformance.ts @suaveplan/logger reports zero errors.
Confirm bunx turbo lint typecheck test --filter=@suaveplan/logger is green.
Confirm bunx turbo test:coverage --filter=@suaveplan/logger reports 100/100/100/100.