Version 2.0.0 - Vercel + Fly.io Serverless Architecture

Major infrastructure migration from DigitalOcean to serverless:

Architecture:
- Application: Vercel (Next.js 15 app + API routes)
- Workers: Fly.io (BullMQ background job processing)
- Database: Prisma Postgres (managed PostgreSQL)
- Redis: Upstash (managed Redis for queues)
- Storage: Vercel Blob (document storage)

Features in this release:
- DocsChatAlpha: Multi-document RAG chat component
- VectorSearchService: Multi-doc search support
- Organization onboarding flow
- Updated deployment documentation

Breaking changes from v1.x:
- No longer self-hosted on DigitalOcean
- Caddy reverse proxy replaced by Vercel Edge Network
- PM2 replaced by Vercel Functions and Fly.io workers