fix: defer incomplete Codex turn exports

[NeuralEmpowerment]

Summary

• defer a trailing source turn until its completed or aborted lifecycle event is present
• prevent separate provisional and finalized OTEL trees for one codex.turn_id
• retain completed-turn sidecar ledger behavior and bump plugin to 0.1.1

Validation

• pnpm lint
• pnpm test (36 tests)

Rationale

The Stop hook can read the rollout before Codex appends task_complete. The previous behavior exported that provisional tree without a ledger entry and exported it again later once completed, producing duplicate Langfuse traces/cost/tool data.