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

src/main.ts

@@ -0,0 +1,81 @@
+import { Application } from "@oak/oak";
+import "@std/dotenv/load";
+
+const app = new Application();
+const PORT = parseInt(Deno.env.get("PORT") || "8000");
+
+// CORS Middleware
+app.use(async (ctx, next) => {
+  ctx.response.headers.set("Access-Control-Allow-Origin", "*");
+  ctx.response.headers.set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS");
+  ctx.response.headers.set("Access-Control-Allow-Headers", "Content-Type, Authorization");
+  
+  if (ctx.request.method === "OPTIONS") {
+    ctx.response.status = 204;
+    return;
+  }
+  
+  await next();
+});
+
+// Logger Middleware
+app.use(async (ctx, next) => {
+  const start = Date.now();
+  await next();
+  const ms = Date.now() - start;
+  console.log(`${ctx.request.method} ${ctx.request.url.pathname} - ${ctx.response.status} (${ms}ms)`);
+});
+
+// Health Check
+app.use(async (ctx, next) => {
+  if (ctx.request.url.pathname === "/health") {
+    ctx.response.body = { 
+      status: "ok", 
+      service: "pulse-crm-backend",
+      version: "0.1.0",
+      timestamp: new Date().toISOString()
+    };
+    return;
+  }
+  await next();
+});
+
+// API Info
+app.use(async (ctx, next) => {
+  if (ctx.request.url.pathname === "/api" || ctx.request.url.pathname === "/api/v1") {
+    ctx.response.body = {
+      name: "Pulse CRM API",
+      version: "1.0.0",
+      docs: "/api/v1/docs",
+      endpoints: {
+        auth: "/api/v1/auth/*",
+        contacts: "/api/v1/contacts/*",
+        companies: "/api/v1/companies/*",
+        deals: "/api/v1/deals/*",
+        pipelines: "/api/v1/pipelines/*",
+        activities: "/api/v1/activities/*",
+        users: "/api/v1/users/*"
+      }
+    };
+    return;
+  }
+  await next();
+});
+
+// 404 Handler
+app.use((ctx) => {
+  ctx.response.status = 404;
+  ctx.response.body = {
+    success: false,
+    error: {
+      code: "NOT_FOUND",
+      message: "Endpoint not found"
+    }
+  };
+});
+
+console.log(`🚀 Pulse CRM Backend starting on port ${PORT}...`);
+console.log(`📚 API Docs: http://localhost:${PORT}/api/v1`);
+console.log(`❤️  Health: http://localhost:${PORT}/health`);
+
+await app.listen({ port: PORT });