The presi module's schema was defined inline in routes.ts but had no
working db:push mechanism — the old references to @presi/server and
@presi/backend no longer exist after consolidation. Extracts schema
into its own file, adds a dedicated drizzle config, and updates the
setup script so tables are actually created.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
