Implement AI orchestration wedding demo

backend/README.md

@@ -0,0 +1,11 @@
+# Backend
+
+FastAPI service containing the REST demo backend, WebSocket streaming gateway, generated tool registry, planner, policy engine, validation layer, executor, memory adapters, and event publisher.
+
+Run locally:
+
+```bash
+uvicorn app.main:app --reload
+```
+
+The planner uses Anthropic Claude when `ANTHROPIC_API_KEY` is configured and otherwise falls back to deterministic intent extraction. The default model is `claude-sonnet-4-6`.