Phase 1: Foundation — backend auth, frontend shell, Docker setup

Backend (FastAPI):
- App factory with async SQLAlchemy 2.0 + PostgreSQL
- Alembic migration for users and sessions tables
- JWT auth (access + refresh tokens, bcrypt passwords)
- Auth endpoints: register, login, refresh, logout, me
- Admin seed script, role-based access deps

Frontend (React + TypeScript):
- Vite + Tailwind CSS + shadcn/ui theme (health-oriented palette)
- i18n with English and Russian translations
- Zustand auth/UI stores with localStorage persistence
- Axios client with automatic token refresh on 401
- Login/register pages, protected routing
- App layout: collapsible sidebar, header with theme/language toggles
- Dashboard with placeholder stats

Infrastructure:
- Docker Compose (postgres, backend, frontend, nginx)
- Nginx reverse proxy with WebSocket support
- Dev override with hot reload

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/i18n.ts

@@ -0,0 +1,25 @@
+import i18n from "i18next";
+import { initReactI18next } from "react-i18next";
+import HttpBackend from "i18next-http-backend";
+import LanguageDetector from "i18next-browser-languagedetector";
+
+i18n
+  .use(HttpBackend)
+  .use(LanguageDetector)
+  .use(initReactI18next)
+  .init({
+    fallbackLng: "en",
+    supportedLngs: ["en", "ru"],
+    interpolation: {
+      escapeValue: false,
+    },
+    backend: {
+      loadPath: "/locales/{{lng}}/translation.json",
+    },
+    detection: {
+      order: ["localStorage", "navigator"],
+      caches: ["localStorage"],
+    },
+  });
+
+export default i18n;