Adds the original NestJS backends (backend, audio-backend), Expo mobile app,
and Astro landing page as-is from the standalone memoro repo. These are
not yet migrated to monorepo standards (migration tracked in memory/CLAUDE.md).
Also adds eslint.config.mjs ignore for apps/*/apps/audio-backend/**
and .prettierignore entries for legacy memoro dirs.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
