chore: execute Sprint 38 technical debt resolution (Type Safety, Zod validation, Vitest, Mock LLM extracted)

fix(arch): HF inbound-only + seedDatabase export + DISABLE_WORKER + DISABLE_WHATSAPP_SEND

fix: resolve tsconfig extension resolution and missing node types

Initial commit: Monorepo setup with React+Vite, Fastify, Prisma, and Docker Compose