Addresses round-1 review on PR #920:
- Delete path now clears the file's dead-letter marker after
release_document_for_user (whose principal-based filter misses the
user-agnostic, principal-less marker), preventing orphan-marker accumulation
for dead-lettered-then-deleted files.
- Oversize PDFs (rejected by the pre-parse size guard, no pipeline_tier stamped)
are now treated as terminal regardless of failing_tier -- no tier can parse an
oversize file -- so they dead-letter instead of falling to the legacy per-user
mark on the inline path.
- Gate the success-path clear on a non-empty etag (an etag-less file can never
have a marker, mirroring is_dead_lettered's early return).
- dead_letter.py: payload typed dict[str, Any] (CLAUDE.md).
Tests: oversize-terminal dead-letter and delete-path marker clear.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
