Restructure standalone traces app into monorepo pattern with mobile + backend + shared types.
Add NestJS backend with Drizzle ORM schema for locations, cities, places, POIs, and AI guides.
Add mobile sync layer, cities tab, and guide generation UI. Fix pre-existing type errors across
mobile codebase, matrix-mana-bot (sendDirectMessage), llm-playground, and all web auth stores
(signUp call signature).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
