docs(insight): fix scheduler comment

[wangyb-A]

Summary

Fix the stale _emit method reference in a Workflow Insight comment after the method was split into _build_record and _schedule_record.

Stacked on #702.

Comment audit

• Timed-out barrier accumulation: fixed in 6c723ba; thread is outdated.
• Implicit RLock: fixed in 6c723ba; thread resolved.
• Duplicate exporter instance: fixed in 7ba7520; thread resolved.
• Unlocked scheduled flag: fixed in 7ba7520; thread resolved.
• Latest Codex review: no actionable findings.
• Latest Claude review: only this documentation nit remained.

Validation

• Insight package Ruff lint and format passed.
• Commit lint passed.
• Source behavior is unchanged; no tests or conformance rerun needed.

[wangyb-A]

Applied directly to #702 as commit 9e0e717; closing this stacked PR as superseded.