Fix environment file and update screenshot.

Summary

- Switch Prisma and all runtime scripts to PostgreSQL (SQLite removed).
- Generate an initial 000_init migration and add migration_lock.toml.
- Add docker-compose.dev.yml for local Postgres, plus npm helpers
(db:up, db:down, db:migrate, db:deploy, db:reset, seed:demo).
- Update env templates and validation (DATABASE_URL, TEST_DATABASE_URL)
and ensure Vitest resets a dedicated rtap_test database.
- Align docs/AGENTS/plan with the new workflow; remove stale SQLite
guidance.
- Refresh dependencies (Next 15.5, Prisma 6.16, TanStack 5.90, tRPC
11.6, ESLint 9.36, etc.).
- CI / Ops

GitHub Actions now provisions Postgres, waits with pg_isready, prepares
a one-off shadow DB, applies migrations, checks for schema drift, and
runs tests against rtap_ci_test.
Testing

npm run check
npm run test

This bumps the docker version to tag 0.4.0