[dmoliveira]

Summary

• Secure retirement marker reads and records with descriptor-relative no-follow custody checks.
• Publish tombstones through exclusive temporary files, no-overwrite links, identity checks, and durability barriers.
• Cover unsafe entries, replacement races, corrupt records, collision behavior, and persistence failures.

Validation

• uv run pytest tests/test_state_safety.py -q (123 passed)
• uv run pytest -q (581 passed)
• uv run ruff check src tests
• git diff --check
• service retirement smoke test

Codememory: task_5640.