Round-4 review nits on PR #920 (none blocking):
- record_document_dead_lettered: enumerate the oversize reason (added this PR)
alongside timeout/oom/error in the docstring + counter comment.
- Note the clear-dead-letter-before-upsert ordering implication (a transient
upsert failure re-parses once, never a silent drop).
- Clarify the orphan sweep's kept counter for tenant-wide dead-letter markers.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>