Provide one creation path for roots and replies, recursive thread loading, body-only updates, root listings, and post voting across PostgreSQL and the in-memory test store.
Adds self-referencing post and post-vote tables, generated schema models, and an idempotent snapshot migration that preserves the legacy tables during the staged application cutover.
Co-authored-by: codegirl-007 <s.raide@gmail.com>
codegirl007