feat: Architektur & Tech-Stack Dokumentation

📐 Architektur:
- Cloud-basiert (SaaS) Entscheidung
- Multi-Tenancy Konzept
- Architektur-Diagramm

🛠️ Tech-Stack:
- Deno + Oak Backend
- PostgreSQL Datenbank
- Vue 3 + PrimeVue Frontend
- Hetzner Hosting (DSGVO)

📁 Projektstruktur:
- src/ mit routes, middleware, services
- docs/ mit Architektur-Doku
- Basis main.ts mit Health Check

README.md

@@ -1,3 +1,80 @@
-# pulse-crm-backend
+# Pulse CRM Backend
 
-Pulse CRM Backend - Deno + PostgreSQL
+🫀 **Der Herzschlag deines Business** - Cloud-basiertes CRM für den deutschen Markt.
+
+## Tech Stack
+
+- **Runtime:** Deno 2.x
+- **Framework:** Oak
+- **Database:** PostgreSQL 16
+- **Auth:** JWT + Argon2
+- **Hosting:** Hetzner Cloud (DSGVO-konform)
+
+## Quick Start
+
+```bash
+# Dependencies cachen
+deno cache src/main.ts
+
+# Development Server
+deno task dev
+
+# Production
+deno task start
+```
+
+## API Endpoints
+
+| Endpoint | Beschreibung |
+|----------|--------------|
+| `GET /health` | Health Check |
+| `GET /api/v1` | API Info |
+| `POST /api/v1/auth/login` | Login |
+| `POST /api/v1/auth/register` | Registrierung |
+| `GET /api/v1/contacts` | Kontakte auflisten |
+| `GET /api/v1/deals` | Deals auflisten |
+| ... | ... |
+
+## Projektstruktur
+
+```
+src/
+├── main.ts           # Entry Point
+├── routes/           # API Routes
+│   ├── auth.ts
+│   ├── contacts.ts
+│   ├── deals.ts
+│   └── ...
+├── middleware/       # Middleware
+│   ├── auth.ts
+│   ├── cors.ts
+│   └── rateLimit.ts
+├── services/         # Business Logic
+├── models/           # Type Definitions
+├── db/               # Database
+│   ├── client.ts
+│   ├── migrate.ts
+│   └── schema.ts
+└── utils/            # Helpers
+```
+
+## Environment Variables
+
+Siehe `.env.example`
+
+## DSGVO
+
+- ✅ Hosting in Deutschland
+- ✅ Verschlüsselung (TLS + AES-256)
+- ✅ Audit Logging
+- ✅ Datenexport
+- ✅ Löschkonzept
+
+## Docs
+
+- [Architektur](docs/ARCHITECTURE.md)
+- [Tech Stack](docs/TECH-STACK.md)
+
+---
+
+© 2026 Pulse CRM - Made with 💚 in Germany